研究者業績

小池 創一

コイケ ソウイチ  (Soichi Koike)

基本情報

所属
自治医科大学 地域医療学センター(地域医療政策部門) 教授

J-GLOBAL ID
201401010545471969
researchmap会員ID
B000237449

外部リンク

論文

 70
  • Akihisa Nakamura, Eiji Satoh, Tatsuya Suzuki, Soichi Koike, Kazuhiko Kotani
    J. Mark. Access Health Policy 12(2) 118-127 2024年6月  査読有り
  • Soichi Koike, Kazuhiko Kotani
    日本臨床検査医学会誌 72(1) 11-18 2024年1月  査読有り筆頭著者
  • Soichi Koike, Hiroo Wada, Sachiko Ohde, Hiroo Ide, Kenichiro Taneda, Takeshi Tanigawa
    BMC Public Health 24 164 2024年1月  査読有り筆頭著者
  • Hiroyuki Teraura, Kazuhiko Kotani, Eiji Sato, Soichi Koike
    The Tohoku Journal of Experimental Medicine 261(4) 273-281 2023年12月  査読有り
  • Soichi Koike, Kentaro Okazaki, Akiko Tokinobu, Masatoshi Matsumoto, Kazuhiko Kotani, Hitomi Kataoka
    Human Resources for Health 21 85 2023年10月  査読有り
  • Daisuke Miyamori, Shuhei Yoshida, Saori Kashima, Soichi Koike, Shinya Ishii, Yuji Okazaki, Kotaro Ikeda, Masatoshi Matsumoto
    Journal of the American Medical Directors Association 24(3) 368-375.e1 2023年3月  査読有り
  • Kotaro Ikeda, Shuhei Yoshida, Yuji Okazaki, Daisuke Miyamori, Saori Kashima, Shinya Ishii, Soichi Koike, Keishi Kanno, Masanori Ito, Masatoshi Matsumoto
    28 31 2023年  査読有り
  • Yosikazu Nakamura, Yuri Matsubara, Koki Kosami, Ryusuke Ae, Teppei Sasahara, Yasuko Aoyama, Soichi Koike, Shizukiyo Ishikawa, Nobuko Makino
    Pediatrics International 64(1) e15268 2022年6月14日  査読有り
  • Yuji Okazaki, Shuhei Yoshida, Saori Kashima, Soichi Koike, Robert Bowman, Masatoshi Matsumoto
    Rural Remote Health . 22(2) 7163 2022年6月  査読有り
  • Yuji Okazaki, Shuhei Yoshida, Saori Kashima, Soichi Koike, Masatoshi Matsumoto
    Headache 62(6) 657-667 2022年6月  査読有り
  • Yuji Okazaki, Shuhei Yoshida, Saori Kashima, Shinya Ishii, Soichi Koike, Masatoshi Matsumoto
    Social Psychiatry and Psychiatric Epidemiology 57(12) 2411-2421 2022年4月26日  査読有り
  • Shuhei Yoshida, Saori Kashima, Shinya Ishii, Soichi Koike, Masatoshi Matsumoto
    BMC Public Health 22(1) 341 2022年2月  査読有り
  • Saori Kashima, Shuhei Yoshida, Yuji Okazaki, Shinya Ishii, Soichi Koike, Masatoshi Matsumoto
    Journal of the American Medical Directors Association 23 1045-1051 2022年2月  査読有り
  • Miyamori D, Yoshida S, Kashima S, Koike S, Ishii S, Matsumoto M
    BMC Geriatrics 22 168 2022年  査読有り
  • Matsumoto M, Matsuyama Y, Kashima S, Koike S, Okazaki Y, Kotani K, Owaki T, Ishikawa S, Iguchi S, Okazaki H, Maeda T
    Human Resources for Health 19(1) 102-102 2021年8月  査読有り
  • Tatsuya Suzuki, Soichi Koike, Masatoshi Matsumoto
    International Journal of Health Geographics 20(1) 21 2021年5月  査読有り
  • Shuhei Yoshida, Masatoshi Matsumoto, Saori Kashima, Soichi Koike, Susumu Tazuma, Takahiro Maeda
    BMC family practice 20(1) 147-147 2019年10月29日  査読有り
    BACKGROUND: Geographical maldistribution of physicians, and their subsequent shortage in rural areas, has been a serious problem in Japan and in other countries. Family Medicine, a new board-certified specialty started 10 years ago in Japan by Japan Primary Care Association (JPCA), may be a solution to this problem. METHODS: We obtained the workplace information of 527 (78.4%) of the 672 JPCA-certified family physicians from an online database. From the national census data, we also obtained the workplace information of board-certified general internists, surgeons, obstetricians/gynaecologists and paediatricians and of all physicians as the same-generation comparison group (ages 30 to 49). Chi-squared test and residual analysis were conducted to compare the distribution between family physicians and other specialists. RESULTS: Five hundred nineteen JPCA-certified family physicians and 137,587 same-generation physicians were analysed. The distribution of family physicians was skewed to municipalities with a lower population density, which shows a sharp contrast to the urban-biased distribution of other specialists. The proportion of family physicians in non-metropolitan municipalities was significantly higher than that expected based on the distribution of all same-generation physicians (p < 0.001). CONCLUSIONS: Family physicians distributed in favour of rural areas much more than any other specialists in Japan. The better balance of family physician distribution reported from countries with a strong primary care orientation seems to hold even in a country where primary care orientation is weak, physician distribution is not regulated, and patients have free access to healthcare. Family physicians comprise only 0.2% of all Japanese physicians. However, if their population grows, they can potentially rectify the imbalance of physician distribution. Government support is mandatory to promote family medicine in Japan.
  • Matsui H, Koike S, Fushimi K, Wada T, Yasunaga H
    Annals of Clinical Epidemiology 1(3) 86-94 2019年10月  査読有り
  • Koike S, Isse T, Kawaguchi H, Ogawa M
    Occupational Medicine 69(2) 139-142 2019年3月  査読有り
  • Koike S, Matsumoto M, Kawaguchi H, Ide H, Atarashi H, Kotani K, Yasunaga H
    BMC Health Services Research 18 615 2018年8月  査読有り
  • Hideaki Kawaguchi, Soichi Koike, Kazuhiko Ohe
    International Journal of Medical Informatics 115 114-119 2018年7月1日  査読有り
    Purpose: Regional differences in the adoption of electronic medical records (EMR) are a major problem, yet little is known about these differences internationally. We analyzed regional differences in EMR adoption in Japan and evaluated factors associated with these differences. Methods: This nationwide ecological study used secondary data from all secondary medical service areas (SMSAs) in fiscal years 2008 (n = 348) and 2014 (n = 344). For each SMSA we collected the following information from a Japanese national database: the number of medical facilities that had adopted EMR, the population density, the average per capita income, the number of working doctors per 1000 people, and the proportion of interns to all working doctors. To adjust for medical facility characteristics in each SMSA, such as number of beds, public versus private hospital, and hospital type (psychiatric or other), we estimated the standardized adoption ratio (SAR) for EMR adoption, modeled on the standardized mortality ratio. We calculated Moran's I for the SAR and investigated whether the SAR had spatial autocorrelations. We evaluated the association between the SAR and regional factors with a conditional autoregressive model. We compared these results in 2008 and 2014, for both hospitals and clinics. Results: While the EMR adoption rate in SMSAs increased, Moran's I of the SAR in hospitals was close to 1 in both 2008 and 2014, and Moran's I of the SAR in clinics increased from 2008 to 2014. For hospitals, there was a significant association between the proportion of interns to all working doctors and the SAR only in 2008. For clinics, average income in the SMSA was positively associated with the SAR, whereas the number of working doctors was negatively associated with the SAR in both 2008 and 2014. Population density was positively associated with the SAR only in 2014. Conclusion: From 2008 to 2014, EMR adoption in Japan generally increased, but geographical differences did not improve. Regional factors associated with the SAR were different for hospitals than for clinics. Therefore, the government should take different approaches for clinics and hospitals to improve regional differences in EMR adoption, especially in providing financial and technical support.
  • Hiroo Ide, Shunsuke Doi, Hidenao Atarashi, Shinsuke Fujita, Soichi Koike
    Human Resources for Health 16(1) 26 2018年6月13日  査読有り
    Background: The uneven geographical distribution of physicians in Japan is a result of those physicians electing to work in certain locations. In order to understand this phenomenon, it is necessary to analyze the geographic movement of physicians across the Japanese landscape. Methods: We obtained individual data on physicians from 1978 to 2012 detailing their attributes, work institutions, and locations. The data are from Japanese governmental sources (the Survey of Physicians, Dentists, and Pharmacists). The total sample size was 122150 physicians, with 77.5% being male and 22.5% female. After obtaining the data, we calculated the geographical distance of each physician's movement by using geographic information systems software (GIS ArcGIS, ESRI, Inc., CA, USA). Geographical distance was then converted into time distance. We compared the resulting median values through nonparametric testing and then conducted a multivariate analysis. Our next step involved the use of an age-period-cohort (APC) model to measure the degree of impact three points of data, experience (experience years), the historical and environmental context of the data (survey year), and physician cohort (registration year) had on the movement of each physician. Results: The ratio of female physicians who selected an urban area as their first working location was higher than that of male physicians. However, the selection of an urban area was becoming more popular as a first working location for both males and females as the year of data increased. The overall distance of geographical movement for female physicians was less than it was for male physicians. Physicians moved the greatest distance between their second and fourth years following license acquisition, at which point the time distance became shorter. The median time distance was 46min in 2000 and 22min in 2008. The physicians in our study did not move far from their first working location, and the overall distance of movement lessened in the more recent years of study. The median distance of movement after 20years was 25.9km for male physicians, and 19.1km for female physicians. The results of the APC model indicated that the effects of experience years (age) gradually declined, that the survey year (period) effects increased, and that the registration year (cohort) effects increased initially before leveling off. Conclusions: The trends following the introduction of the new mandatory training system in 2004 may imply that the concentration of physicians in Japan's urban areas is expected to increase. After 2000, the effect of that period on physicians explains their geographical movements more so than the factor of their age.
  • Masatoshi Matsumoto, Kazuki Kimura, Kazuo Inoue, Saori Kashima, Soichi Koike, Susumu Tazuma
    PLoS ONE 13(6) e0198317 2018年6月1日  査読有り
    Background The disparity in the number of urban and rural physicians is a social problem in Japan. There may also be a disparity in the age of physicians. This study longitudinally examines both geographic and age distributions of physicians. Methods Individual data from the Survey of Physicians, Dentists and Pharmacists in 1994, 2004 and 2014 and municipality data from the National Population Census were used. The 2015 municipality border was applied to all years, and all municipalities were classified into equal-size quintiles based on population density. Both municipalities and physicians were longitudinally observed. Results Between 1994 and 2014, the number of physicians per 100,000 population increased by 31.8% in the most urban group of municipalities and 17.4% in the most rural group. The average age of physicians was highest in the most rural and lowest in the most urban group. The difference in average age between the urban and rural physicians widened from 2.1 years in 1994 to 6.0 years in 2014. This disparity is particularly pronounced among hospital physicians (from 1.5 years in 1994 to 7.6 years in 2014). In the most rural group, the number of hospital physicians younger than 40 years old has decreased by 59.4%, while the number of those 55–70 has grown by 153% and the number older than 70 years old by 41.0%. Between 1994 and 2004, only 23.0% of hospital physicians younger than 40 years old were retained in the most rural group the retention rate fell to 19.3% between 2004 and 2014, while the rates increased in older physicians. Conclusions The uneven distribution of physicians is increasing in Japan, as is the aging of rural hospital physicians. Shortage of physicians in rural areas may be more serious than that shown as their headcount.
  • Hideaki Kawaguchi, Soichi Koike, Ryota Sakurai, Kazuhiko Ohe
    International Journal of Health Geographics 17(1) 3 2018年5月21日  査読有り
    Background: Coronary computed tomography angiography (CTA) has demonstrated high diagnostic accuracy for detection of coronary artery stenosis, and healthcare providers can detect coronary artery disease in earlier stages before it develops into more serious clinical conditions such as acute myocardial infarction (AMI). We hypothesized that the mortality ratio of AMI in regions with a higher density of coronary CTA is lower than that in regions with a lower density of coronary CTA. Methods: This ecological and cross-sectional study using secondary data targeted all secondary medical service areas (SMSAs) in Japan (n=349). We obtained the numbers of cardiologists, institutions with coronary CTA, and institutions with a cardiac catheterization laboratory (CCL) as medical resources, socioeconomic factors, lifestyle factors, exercise habit factors, and AMI mortality data from a Japanese national database. We evaluated the association between the number of these medical resources and the standardized mortality ratio (SMR) of AMI in each SMSA using a hierarchical Bayesian model accounting for spatial autocorrelation (i.e., a conditional autoregressive model). We assumed a Poisson distribution for the observed number of AMI-related deaths and set the expected number of AMI-related deaths as the offset variable. Results: The number of institutions with coronary CTA was negatively and significantly associated with the SMR of AMI (relative risk [RR] 0.900 95% credible interval [CI] 0.848-0.953), while the SMR in each SMSA was not significantly associated with the number of either cardiologists (RR 0.997 95% CI 0.988-1.004) or institutions with a CCL (RR 1.026 95% CI 0.963-1.096). Conclusions: We observed a significant association between the number of institutions with coronary CTA and the SMR of AMI. Effective allocation of coronary CTA in each region is recommended, and it would be important to clarify the standing position of coronary CTA in regional networking for AMI treatment in the future.
  • 中村 好一, 松原 優里, 笹原 鉄平, 古城 隆雄, 阿江 竜介, 青山 泰子, 牧野 伸子, 小池 創一, 石川 鎮清
    日本公衆衛生雑誌 65(2) 72-82 2018年2月  
    目的 地方紙における遺族の自己申告型死亡記事の記載事項を集計し、その地域での死亡やそれに伴う儀式の実態を明らかにするとともに、死亡記事のデータベースとしての利点と問題点を明らかにする。方法 栃木の地方紙である下野新聞の自己申告型死亡記事「おくやみ」欄に掲載された2011〜2015年の栃木県内の死亡者全員のデータを集計解析し、一部の結果は人口動態統計と比較した。観察項目は掲載年月日、市町村、住所の表示(市町村名のみ、町名・字まで、番地まで含めた詳細な住所)、氏名、性別、死亡年月日、死因、死亡時年齢、通夜・告別式などの名称、通夜などの年月日、告別式などの年月日、喪主と喪主の死亡者との続柄の情報である。結果 観察期間中の掲載死亡者数は69,793人で、同時期の人口動態統計による死亡者数の67.6%であった。人口動態統計と比較した掲載割合は男女で差がなく、小児期には掲載割合が低く、10歳代で高く、20歳代で低下し、以降は年齢とともに上昇していた。市町別の掲載割合は宇都宮市や小山市など都市化が進んだ地域では低く、県東部や北部で高い市町がみられた。最も掲載割合が高かったのは茂木町(88.0%)、低かったのは野木町(38.0%)であった。死亡日から通夜や告別式などの日数から、東京などで起こっている火葬場の供給不足に起因する火葬待ち現象は起こっていないことが判明した。六曜の友引の日の告別式はほとんどなく、今後、高齢者の増加に伴う死者の増加によって火葬場の供給不足が起こった場合には、告別式と火葬を切り離して友引に火葬を行うことも解決策の1つと考えられた。死亡者の子供、死亡者の両親、死亡者の子供の配偶者が喪主の場合には、喪主は男の方が多いことが判明した。老衰、自殺、他殺の解析から、掲載された死因の妥当性は低いことが示された。結論 栃木県の地方紙である下野新聞の自己申告型死亡記事「おくやみ」欄の5年分の観察を行い、実態を明らかにした。約3分の2に死亡が掲載されており、データベースとしての使用に一定の価値があると考えられたが、記載された死因の妥当性は低いことが判明した。(著者抄録)
  • Soichi Koike, Masatoshi Matsumoto, Hiroo Ide, Hideaki Kawaguchi, Masahisa Shimpo, Hideo Yasunaga
    BMC MEDICAL EDUCATION 17 83 2017年5月  査読有り
    Background: Establishing and managing a board certification system is a common concern for many countries. In Japan, the board certification system is under revision. The purpose of this study was to describe present status of internal medicine specialist board certification, to identify factors associated with maintenance of board certification and to investigate changes in area of practice when physicians move from hospital to clinic practice. Methods: We analyzed 2010 and 2012 data from the Survey of Physicians, Dentists and Pharmacists. We conducted logistic regression analysis to identify factors associated with the maintenance of board certification between 2010 and 2012. We also analyzed data on career transition from hospitals to clinics for hospital physicians with board certification. Results: It was common for physicians seeking board certification to do so in their early career. The odds of maintaining board certification were lower in women and those working in locations other than academic hospitals, and higher in physicians with subspecialty practice areas. Among hospital physicians with board certification who moved to clinics between 2010 and 2012, 95.8% remained in internal medicine or its subspecialty areas and 87.7% maintained board certification but changed their practice from a subspecialty area to more general internal medicine. Conclusion: Revisions of the internal medicine board certification system must consider different physician career pathways including mid-career moves while maintaining certification quality. This will help to secure an adequate number and distribution of specialists. To meet the increasing demand for generalist physicians, it is important to design programs to train specialists in general practice.
  • Hidenao Atarashi, Hiroo Ide, Soichi Koike
    Journal of Clinical Engineering 41(3) 127-133 2016年6月21日  査読有り
    To ensure the safety of medical equipment, appointing medical equipment safety managers (MESMs) in medical institutions was made compulsory in Japan in 2007. This study aimed to describe the current status of clinical engineers (CEs) and analyze changes in the specialties of those selected as MESMs in Japan. We analyzed 2008 and 2011 government census data on hospitals. The proportion of hospitals where CEs were MESMs increased significantly, from 16.6% in 2008 to 18.5% in 2011. Although CEs are optimal as MESMs in terms of expertise, only one-third of hospitals (2,743/8,157) employed CEs.
  • Miho Ishimaru, Sachiko Ono, Hideo Yasunaga, Hiroki Matsui, Soichi Koike
    Journal of public health dentistry 76(3) 241-8 2016年6月  査読有り
    OBJECTIVES: Appropriate health policies for the supply of dentists have been an ongoing issue in many developed countries. The purpose of this study was to estimate the future distribution of dentists with different working statuses in Japan and to discuss policy implications about the supply of dentists in any country. METHODS: This was a retrospective cohort study using data from the National Survey of Physicians, Dentists and Pharmacists for 1972-2012. Based on data from the 2010 and 2012 surveys, we calculated by means of a Markov model the future number of dentists with different working statuses until 2042 according to sex. RESULTS: We estimated that the total number of active dentists will decrease from 2012 to 2042. The number of active dentists per 1,000 population was predicted to reach a peak in 2018, decrease by 4.2% from 2012 to 2038, and thereafter slightly increase. With regard to working status, the number of dentists with their own practices per 1,000 people was predicted to have reached a peak in 2014 and decrease by 22.0% until 2042. We estimated that the number of dentists used in dental clinics per 1,000 population will increase continuously between 2012 and 2042 by 20.0%. CONCLUSIONS: Our study suggests that maintaining this supply of dentists may lead to maldistribution of their working status in the future.
  • Soichi Koike, Atsushi Shimizu, Masatoshi Matsumoto, Hiroo Ide, Hidenao Atarashi, Hideo Yasunaga
    SURGERY TODAY 46(6) 661-667 2016年6月  査読有り
    To investigate the career pathways of board-certified surgeons' and the factors associated with them maintaining their certification in Japan. We analyzed data from the surveys of physicians, dentists and pharmacists. A multivariate logistic regression model was used to investigate whether factors such as gender, year of registration, place of work, and subspecialty board certification were associated with maintaining board certification. Most Japanese surgeons attain board certification within 5-10 years of initial medical registration. After adjusting for possible confounding factors, the odds of maintaining board certification were significantly lower for women, those who were beyond 20 years post-registration, those who worked in hospitals other than academic hospitals or clinics, and those who had board certification in surgery only. Of the total board-certified surgeons analyzed, 93.2 % continued to work in hospitals and 2.8 % moved to clinics within 2 years. Of those who moved from hospitals to clinics, half continued to practice surgery, while nearly 40 % changed their specialty to internal medicine. It is necessary to establish a special training system for mature surgeons who move from surgery to general practice later in their careers. As the number of female surgeon increases, a support system is also required to secure the future supply of surgeons.
  • Hideaki Kawaguchi, Soichi Koike
    PLOS ONE 11(2) 2016年2月  査読有り
    Background Regional disparity in suicide rates is a serious problem worldwide. One possible cause is unequal distribution of the health workforce, especially psychiatrists. Research about the association between regional physician numbers and suicide rates is therefore important but studies are rare. The objective of this study was to evaluate the association between physician numbers and suicide rates in Japan, by municipality. Methods The study included all the municipalities in Japan (n = 1,896). We estimated smoothed standardized mortality ratios of suicide rates for each municipality and evaluated the association between health workforce and suicide rates using a hierarchical Bayesian model accounting for spatially correlated random effects, a conditional autoregressive model. We assumed a Poisson distribution for the observed number of suicides and set the expected number of suicides as the offset variable. The explanatory variables were numbers of physicians, a binary variable for the presence of psychiatrists, and social covariates. Results After adjustment for socioeconomic factors, suicide rates in municipalities that had at least one psychiatrist were lower than those in the other municipalities. There was, however, a positive and statistically significant association between the number of physicians and suicide rates. Conclusions Suicide rates in municipalities that had at least one psychiatrist were lower than those in other municipalities, but the number of physicians was positively and significantly related with suicide rates. To improve the regional disparity in suicide rates, the government should encourage psychiatrists to participate in community-based suicide prevention programs and to settle in municipalities that currently have no psychiatrists. The government and other stakeholders should also construct better networks between psychiatrists and non-psychiatrists to support sharing of information for suicide prevention.
  • Soichi Koike, Masatoshi Matsumoto, Hiroo Ide, Saori Kashima, Hidenao Atarashi, Hideo Yasunaga
    INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS 15 4 2016年1月  査読有り
    Background: In Japan, the number of obstetrics facilities has steadily decreased and the selection and concentration of obstetrics facilities is progressing rapidly. Obstetrics services should be concentrated in fewer hospitals to improve quality of care and reduce the workload of obstetricians. However, the impact of this intensification of services on access to obstetrics hospitals is not known. We undertook a simulation to examine how the intensification of obstetrics services would affect access to hospitals based on a variety of scenarios, and the implications for health policy. Methods: The female population aged between 15 and 49 living within a 30-min drive of an obstetrics hospital was calculated using a Geographic Information System for three possible intensification scenarios: Scenario 1 retained facilities with a higher volume of deliveries without considering the geographic boundaries of Medical Service Areas (MSAs, zones of healthcare administration and management); Scenario 2 prioritized retaining at least one hospital in each MSA and then retained higher delivery volume institutions, while Scenario 3 retained facilities to maximize population coverage using location-allocation modeling. We also assessed the impact of concentrating services in academic hospitals and specialist perinatal medical centers (PMCs) alone. Results: In 2011, 95.0 % of women aged 15-49 years lived within a 30-min drive of one of 1075 obstetrics hospitals. This would fall to 82.7 % if obstetrics services were intensified into academic hospitals and general and regional PMCs. If 55.0 % of institutions provided obstetrics services, the coverage would be 87.6 % in Scenario 1, whereas intensification based on access would achieve over 90.5 % coverage in Scenario 2 and 93.9 % in Scenario 3. Conclusions: Intensification of obstetrics facilities impairs access, but a greater caseload and better staffing have the potential advantages of better clinical outcomes and reduced costs. It is essential to consult residents of hospital catchment areas when reorganizing clinical services; a simulation is a useful means of informing these important discussions.
  • Masatoshi Matsumoto, Soichi Koike, Saori Kashima, Kazuo Awai
    PLOS ONE 10(9) 2015年9月  査読有り
    Background Japan has the most CT and MRI scanners per unit population in the world, and as these technologies spread, their geographic distribution is becoming equalized. In contrast, the number of radiologists per unit population in Japan is the lowest among OECD countries and their geographic distribution is unknown. Likewise, little is known about the use of teleradiology, which can compensate for the uneven distribution of radiologists. Methods Based on the Survey of Physicians, Dentists and Pharmacists and the Static Survey of Medical Institutions by the Ministry of Health, Labour and Welfare, a dataset of radiologists and CT and MRI utilizations in each of Japan's 1811 municipalities was created. The inter-municipality equity of the number of radiologists was evaluated using Gini coefficient. Logistic regression analysis, based on Static Survey data, was performed to evaluate the association between hospital location and teleradiology use. Results Between 2006 and 2012 the number of radiologists increased by 21.7%, but the Gini coefficient remained unchanged. The number of radiologists per 1,000 CT (MRI) utilizations decreased by 17.9% (1.0%); the number was highest in metropolis and lowest in town/village and the disparity has widened from 1.9 to 2.2 (1.6 to 2.0) times. The number of hospitals and clinics using teleradiology has increased (by 69.6% and 18.1%, respectively). Hospitals located in towns/villages (odds ratio 1.61; 95% confidence interval 1.26-2.07) were more likely to use teleradiology than those in metropolises. Conclusions Contrary to the CT and MRI distributions, radiologist distribution has not been evened out by the increase in their number; in other words, the distribution of radiologists was not affected by market-derived spatial competition force. As a consequence, the gap of the radiologist shortage between urban and rural areas is increasing. Teleradiology, which is one way to ameliorate this gap, should be encouraged.
  • Masatoshi Matsumoto, Soichi Koike, Shigeki Matsubara, Saori Kashima, Hiroo Ide, Hideo Yasunaga
    JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH 41(6) 919-925 2015年6月  査読有り
    AimA shortage of obstetricians with increased workload is a social problem in Japan. In response, the government and professional bodies have accelerated the selection and concentration' of obstetric facilities. The aim of this study was to evaluate the recent trend of selection and concentration. MethodsWe used data on the number of deliveries and of obstetricians in each hospital and clinic in Japan, according to the Static Survey of Medical Institutions in 2005, 2008 and 2011. To evaluate the inter-facility equality of distribution of the number of deliveries, number of obstetricians and number of deliveries per obstetrician, Gini coefficients were calculated. ResultsThe number of obstetric hospitals decreased by 20% and the number of deliveries per hospital increased by 26% between 2005 and 2011. Hospital obstetricians increased by 16% and the average number of obstetricians per hospital increased by 19% between 2008 and 2011. Gini coefficient of deliveries has significantly decreased. In contrast, Gini coefficient of deliveries per obstetrician has significantly increased. The degree of increase in obstetricians and of decrease in deliveries per obstetrician was largest at the hospitals with the highest proportion of cesarean sections. The proportion of obstetric hospitals with the optimal volume of deliveries and obstetricians, as defined by Japan Society of Obstetrics and Gynecology, was 4% in 2008, and it had doubled to 8.1% 3 years later. ConclusionThe selection and concentration of obstetric facilities is progressing rapidly and effectively in Japan.
  • Masatoshi Matsumoto, Soichi Koike, Saori Kashima, Kazuo Awai
    PLOS ONE 10(5) 2015年5月  査読有り
    Background Japan has the most CT and MRI scanners per unit population in the world; however, the geographic distribution of these technologies is currently unknown. Moreover, nothing is known of the cause-effect relationship between the number of diagnostic imaging devices and their geographic distribution. Methods Data on the number of CT, MRI and PET devices and that of their utilizations in all 1829 municipalities of Japan was generated, based on the Static Survey of Medical Institutions conducted by the government. The inter-municipality equity of the number of devices or utilizations was evaluated with Gini coefficient. Results Between 2005 and 2011, the number of CT, MRI and PET devices in Japan increased by 47% (8789 to 12945), 19% (5034 to 5990) and 70% (274 to 466), respectively. Gini coefficient of the number of devices was largest for PET and smallest for CT (p for PET-MRI difference &lt;0.001; MRI-CT difference &lt;0.001). For all three modalities, Gini coefficient steadily decreased (p for 2011-2005 difference: &lt;0.001 for CT; 0.003 for MRI; and &lt;0.001 for PET). The number of devices in old models (single-detector CT, MRI&lt;1.5 tesla, and conventional PET) decreased, while that in new models (multi-detector CT, MRI &gt;= 1.5 tesla, and PET-CT) increased. Gini coefficient of the old models increased or remained unchanged (increase rate of 9%, 3%, and -1%; p for 2011-2008 difference &lt;0.001, 0.072, and 0.562, respectively), while Gini coefficient of the new models decreased (-10%, -9%, and -10%; p for 2011-2008 difference &lt;0.001, &lt;0.001, and &lt;0.001 respectively). Similar results were observed in terms of utilizations. Conclusions The more abundant a modality, the more equal the modality's distribution. Any increase in the modality made its distribution more equal. The geographic distribution of the diagnostic imaging technology in Japan appears to be affected by spatial competition derived from a market force.
  • Soichi Koike, Yuji Furui
    HEALTH POLICY 110(1) 94-100 2013年4月  査読有り
    Objectives: The objective of this study was to examine the effects of home-based long-term care insurance services on an increase in care need levels and discuss its policy implications. Methods: We analyzed care need certification and long-term care service use data for 3006 non-institutionalized elderly persons in a Tokyo ward effective as of October 2009 and 2010. Individual care need assessment intervals and their corresponding changes in care need level were calculated from data at two data acquisition points of care need assessment. Those who had been certified but did not use any long-term care insurance service were defined as the control group. The Cox proportionate hazard model was used to determine whether the use of a long-term care insurance service is associated with increased care need level. Results: After adjusting for sex, age, and care need level, the hazard ratio for the probability of increased care need level among service users was calculated as 0.75 (95% confidence interval, 0.64-0.88; p &lt; 0.001). Conclusions: Home-based long-term care service use may prevent an increase in care need level. Administrative data on care need certification and services use could be an effective tool for evaluating the long-term care insurance system. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
  • Manabu Akahane, Seizan Tanabe, Toshio Ogawa, Soichi Koike, Hiromasa Horiguchi, Hideo Yasunaga, Tomoaki Imamura
    PEDIATRIC CRITICAL CARE MEDICINE 14(2) 130-136 2013年2月  査読有り
    Objectives: There is a paucity of data examining nationwide population-based incidences and outcomes of pediatric out-of-hospital cardiac arrest. The objective of this study is to describe the detailed characteristics of pediatric out-of-hospital cardiac arrest by scholastic age category and to evaluate the impact of bystander cardiopulmonary resuscitation and public access-automated external defibrillators on the 1-month survival and favorable neurological status of pediatric out-of-hospital cardiac arrest patients. Design: A nationwide, population-based, observational study. Setting: Nationwide emergency medical system in Japan. Patients: Out-of-hospital cardiac arrest patients aged &lt;= 18 yr. Measurements and Main Results: We identified 7,624 pediatric out-of-hospital cardiac arrest patients (&lt;= 18 yr old) from a nationwide population-based out-of-hospital cardiac arrest database in Japan from 2005 to 2008 and stratified them into five categories by scholastic age. The overall rates of 1-month survival and favorable neurological outcomes were 11.0% and 5.1%, respectively. Bystander cardiopulmonary resuscitation resulted in a significant improvement in both 1-month survival (odds ratio 2.81; 95% confidence interval 2.30-3.44) and favorable neurological outcomes (odds ratio 4.55; 95% confidence interval 3.35-6.18). Performing public access-automated external defibrillators had a significant effect on the 1-month survival rate (odds ratio 3.51; 95% confidence interval 1.81-6.81) and favorable neurological outcomes (odds ratio 5.13; 95% confidence interval 2.64-9.96). Conclusions: This study demonstrated that bystander cardiopulmonary resuscitation and public access-automated external defibrillators had a significant impact on the outcomes of pediatric out-of-hospital cardiac arrest. The improved survival associated with bystander cardiopulmonary resuscitation and public access-automated external defibrillators are clinically important and are of major public health importance for school-aged out-of-hospital cardiac arrest patients. (Pediatr Crit Care Med 2013; 14:130-136)
  • Seizan Tanabe, Hideo Yasunaga, Soichi Koike, Manabu Akahane, Toshio Ogawa, Hiromasa Horiguchi, Tetsuo Hatanaka, Hiroyuki Yokota, Tomoaki Imamura
    Critical care (London, England) 16(6) R219 2012年11月13日  査読有り
    INTRODUCTION: Conventional monophasic defibrillators for out-of-hospital cardiac-arrest patients have been replaced with biphasic defibrillators. However, the advantage of biphasic over monophasic defibrillation for pediatric out-of-hospital cardiac-arrest patients remains unknown. This study aimed to compare the survival outcomes of pediatric out-of-hospital cardiac-arrest patients who underwent monophasic defibrillation with those who underwent biphasic defibrillation. METHODS: This prospective, nationwide, population-based observational study included pediatric out-of-hospital cardiac-arrest patients from January 1, 2005, to December 31, 2009. The primary outcome measure was survival at 1 month with minimal neurologic impairment. The secondary outcome measures were survival at 1 month and the return of spontaneous circulation before hospital arrival. Multivariable logistic regression analysis was performed to identify the independent association between defibrillator type (monophasic or biphasic) and outcomes. RESULTS: Among 5,628 pediatric out-of-hospital cardiac-arrest patients (1 through 17 years old), 430 who received defibrillation shock with monophasic or biphasic defibrillator were analyzed. The number of patients who received defibrillation shock with monophasic defibrillator was 127 (30%), and 303 (70%) received defibrillation shock with biphasic defibrillator. The survival rates at 1 month with minimal neurologic impairment were 17.5% and 24.4%, the survival rates at 1 month were 32.3% and 35.6%, and the rates of return of spontaneous circulation before hospital arrival were 24.4% and 27.4% in the monophasic and biphasic defibrillator groups, respectively. Hierarchic logistic regression analyses by using generalized estimation equations found no significant difference between the two groups in terms of 1-month survival with minimal neurologic impairment (odds ratio (OR), 1.57; 95% confidence interval (CI), 0.87 to 2.83; P = 0.14) and 1-month survival (OR, 1.38; 95% CI, 0.87 to 2.18; P = 0.17). CONCLUSIONS: The present nationwide population-based observational study could not confirm an advantage of biphasic over monophasic defibrillators for pediatric OHCA patients.
  • Manabu Akahane, Seizan Tanabe, Soichi Koike, Toshio Ogawa, Hiromasa Horiguchi, Hideo Yasunaga, Tomoaki Imamura
    International journal of emergency medicine 5(1) 41-41 2012年11月9日  査読有り
    UNLABELLED: BACKGROUND: A growing elderly population along with advances in equipment and approaches for pre-hospital resuscitation necessitates up-to-date information when developing policies to improve elderly out-of-hospital cardiac arrest (OHCA) outcomes. We examined the effects of bystander type (family or non-family) intervention on 1-month outcomes of witnessed elderly OHCA patients. METHODS: Data from a total of 85,588 witnessed OHCA events in patients aged ≥65 years, which occurred from 2005 to 2008, were obtained from a nationwide population-based database. Patients were stratified into three age categories (65-74, 75-84, ≥85 years), and the effects of bystander type (family or non-family) on initial cardiac rhythm, rate of bystander cardiopulmonary resuscitation (CPR), and 1-month outcomes were assessed. RESULTS: The overall survival rate was 6.9% (65-74 years: 9.8%, 75-84 years: 6.9%, ≥85 years: 4.6%). Initial VF/VT was recorded in 11.1% of cases with a family bystander and 12.9% of cases with a non-family bystander. The rate of bystander CPR was constant across the age categories in patients with a family bystander and increased with advancing age categories in patients with a non-family bystander. Patients having a non-family bystander were associated with significantly higher 1-month rates of survival (OR: 1.26; 95% CI: 1.19-1.33) and favorable neurological status (OR: 1.47; 95% CI: 1.34-1.60). CONCLUSIONS: Elderly patient OHCA events witnessed by a family bystander were associated with worse 1-month outcomes than those witnessed by a non-family bystander. Healthcare providers should consider targeting potential family bystanders for CPR education to increase the rate and quality of bystander CPR.
  • Seizan Tanabe, Hideo Yasunaga, Toshio Ogawa, Soichi Koike, Manabu Akahane, Hiromasa Horiguchi, Tetsuo Hatanaka, Hiroyuki Yokota, Tomoaki Imamura
    CIRCULATION-CARDIOVASCULAR QUALITY AND OUTCOMES 5(5) 689-696 2012年9月  査読有り
    Background-The use and popularity of the biphasic waveform defibrillator as a replacement for the monophasic waveform defibrillator are increasing, but it is unclear whether this can improve the rate of survival among out-of-hospital cardiac arrest patients. This study aimed to verify the hypothesis that the outcome of out-of-hospital cardiac arrest patients who received defibrillation shock with the biphasic waveform defibrillator was better than that of patients who received defibrillation shock with the monophasic defibrillator. Methods and Results-This prospective, nationwide, population-based, observational study included 21 172 out-of-hospital cardiac arrest patients with initial ventricular fibrillation or pulseless ventricular tachycardia from January 1, 2005, through December 31, 2007. Defibrillation shock was performed by monophasic defibrillator on 8224 (39%) patients and by biphasic defibrillator on 12 948 (61%) patients. The rate of survival at 1 month with minimal neurological impairment was 11.6% (951/8192) in the monophasic defibrillator group and 12.8% (1653/12928) in the biphasic defibrillator group. Hierarchical logistic regression analysis using a generalized estimation equation showed no significant difference between the biphasic and monophasic groups in 1-month survival with minimal neurological impairment (adjusted odds ratio, 1.07; 95% confidence interval, 0.91-1.26; P=0.42). Confirmatory propensity score analyses showed similar results. Conclusions-Although monophasic defibrillators are being replaced by biphasic defibrillators, our nationwide population-based observational study failed to demonstrate a statistically significant association between defibrillation waveform and 1-month survival rate with minimal neurological impairment. (Circ Cardiovasc Qual Outcomes. 2012;5:689-696.)
  • Tomoko Kodama, Soichi Koike, Shinya Matsumoto, Hiroo Ide, Hideo Yasunaga, Tomoaki Imamura
    HEALTH POLICY 105(2-3) 214-220 2012年5月  査読有り
    Background: The percentage of females in the physician workforce is increasing in Japan, as in other countries: however, the working status of female physicians has not been sufficiently investigated. Methods: Original data were obtained from the National Survey of Physicians (NSP) conducted by the Ministry of Health. Labour and Welfare, Japan, from 1984 to 2004. We examined the trend of female physicians' areas of practice and analyzed their leave, return to work, and change in areas of practice using cohort data. Results: The percentage of female physicians has increased significantly in recent generations, especially in surgery, surgical subareas of practice, and obstetrics and gynecology. A remarkable increase was found in obstetrics and gynecology among women under 29 years old from 15.4 to 66.2%. The total number of female physicians on leave has been higher than the number of female physicians returning since 1998. The average percentage of those who changed their area of practice was high in surgery (20.7%) and low in pediatrics (5.0%) and obstetrics and gynecology (1.7%). Conclusions: A strategic plan is needed for future health policy to plan for the physician workforce, especially for the areas of practice with increasing proportions of young female physicians. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
  • Manabu Akahane, Toshio Ogawa, Seizan Tanabe, Soichi Koike, Hiromasa Horiguchi, Hideo Yasunaga, Tomoaki Imamura
    CRITICAL CARE MEDICINE 40(5) 1410-1416 2012年5月  査読有り
    Objective: Most previous studies of pediatric out-of-hospital cardiac arrest have typically examined relatively small datasets from small study regions. Although several studies have reported the impact on adult out-of-hospital cardiac arrest, little information is available on the impact of telephone dispatcher assistance on the outcomes of pediatric out-of-hospital cardiac arrest. We set out to examine the impact of cardiopulmonary resuscitation instruction by telephone dispatcher on the outcomes of pediatric out-of-hospital cardiac arrest. Design: Population-based, observational study. Setting: Japan-wide population-based setting. Patients: We identified 1,780 pediatric out-of-hospital cardiac arrest patients (67.8% male) with witnessed collapse from a nationwide, population-based, out-of-hospital cardiac arrest database. Intervention: None. Measurement and Main Results: We assessed the impact of telephone dispatcher assistance on the outcomes of 1-month survival rates and favorable neurologic status among the groups. The overall rate of bystander-performed chest compression and mouth-to-mouth ventilation among the witnessed pediatric out-of-hospital cardiac arrests were 39.5% and 25.6%, respectively. Telephone dispatcher assistance was offered in 28.4% of the witnessed pediatric out-of-hospital cardiac arrest cases and resulted in a significant increase in both chest compression (adjusted odds ratio 6.04; 95% confidence interval 4.72-7.72) and mouth-to-mouth ventilation (adjusted odds ratio 3.10; 95% confidence interval 2.44-3.95), and a significant improvement in 1-month survival rate (adjusted odds ratio 1.46; 95% confidence interval 1.05-2.03), but no significant effect on favorable neurologic outcomes at 1 month (adjusted odds ratio 1.15; 95% confidence interval 0.70-1.88). Potential confounding factors included age categories, sex, bystander type, cause of cardiac arrest, bystander cardiopulmonary resuscitation, and attempted defibrillation. Conclusions: Telephone dispatcher assistance could significantly increase bystander cardiopulmonary resuscitation among witnessed pediatric out-of-hospital cardiac arrests. Although there was only a small, nonsignificant effect on the improvement in favorable neurologic outcome at 1 month, the improved survival associated with telephone dispatcher assistance in pediatric out-of-hospital cardiac arrest is clinically important, and is of major public health importance. In cases where cardiac arrest was uncertain from the bystander's replies during the call to emergency medical services, telephone dispatcher assistance was not offered, which could affect the adjusted odds ratio of the present study. (Crit Care Med 2012; 40: 1410-1416)
  • Soichi Koike, Hiroo Ide, Tomoko Kodama, Shinya Matsumoto, Hideo Yasunaga, Tomoaki Imamura
    ACADEMIC MEDICINE 87(5) 662-667 2012年5月  査読有り
    Purpose To investigate career trends for physician-scientists in Japan. Method The authors analyzed 1996-2008 biennial census survey data from Japan's national physician registry to examine trends over time in the numbers and proportion of physician-scientists by sex and years since registration. They also analyzed the transition of registered physicians into and out of the physician-consecutive surveys (1996-1998 and 2006-2008). Results The number of physician-scientists between 1996 and 2008 was stable, with a low of 4,893 and a high of 5,325. The number of younger physician-scientists (those registered 0-4 years at the time of the surveys) declined sharply, however, from 828 in 1996 to 253 in 2008. The number of female physician-scientists increased from 528 in 1996 to 746 in 2008. Across the two survey periods, about 30% of physician-scientists left the career path, but this attrition was offset by about the same number of new individuals entering the field. Conclusions Although the total number of physician-scientists was relatively unchanged during the period studied, it is essential that educators and policy makers develop approaches to address underlying demographic changes to ensure an adequate age- and gender-balanced
  • Satoshi Ezoe, Takeo Morooka, Tatsuya Noda, Miriam Lewis Sabin, Soichi Koike
    PLOS ONE 7(1) 2012年1月  査読有り
    Background: Men who have sex with men (MSM) are one of the groups most at risk for HIV infection in Japan. However, size estimates of MSM populations have not been conducted with sufficient frequency and rigor because of the difficulty, high cost and stigma associated with reaching such populations. This study examined an innovative and simple method for estimating the size of the MSM population in Japan. We combined an internet survey with the network scale-up method, a social network method for estimating the size of hard-to-reach populations, for the first time in Japan. Methods and Findings: An internet survey was conducted among 1,500 internet users who registered with a nationwide internet-research agency. The survey participants were asked how many members of particular groups with known population sizes (firepersons, police officers, and military personnel) they knew as acquaintances. The participants were also asked to identify the number of their acquaintances whom they understood to be MSM. Using these survey results with the network scale-up method, the personal network size and MSM population size were estimated. The personal network size was estimated to be 363.5 regardless of the sex of the acquaintances and 174.0 for only male acquaintances. The estimated MSM prevalence among the total male population in Japan was 0.0402% without adjustment, and 2.87% after adjusting for the transmission error of MSM. Conclusions: The estimated personal network size and MSM prevalence seen in this study were comparable to those from previous survey results based on the direct-estimation method. Estimating population sizes through combining an internet survey with the network scale-up method appeared to be an effective method from the perspectives of rapidity, simplicity, and low cost as compared with more-conventional methods.
  • Seizan Tanabe, Hideo Yasunaga, Soichi Koike, Manabu Akahane, Toshio Ogawa, Hiromasa Horiguchi, Tetsuo Hatanaka, Hiroyuki Yokota, Tomoaki Imamura
    CRITICAL CARE 16(6) 2012年  査読有り
    Introduction: Conventional monophasic defibrillators for out-of-hospital cardiac-arrest patients have been replaced with biphasic defibrillators. However, the advantage of biphasic over monophasic defibrillation for pediatric out-of-hospital cardiac-arrest patients remains unknown. This study aimed to compare the survival outcomes of pediatric out-of-hospital cardiac-arrest patients who underwent monophasic defibrillation with those who underwent biphasic defibrillation. Methods: This prospective, nationwide, population-based observational study included pediatric out-of-hospital cardiac-arrest patients from January 1, 2005, to December 31, 2009. The primary outcome measure was survival at 1 month with minimal neurologic impairment. The secondary outcome measures were survival at 1 month and the return of spontaneous circulation before hospital arrival. Multivariable logistic regression analysis was performed to identify the independent association between defibrillator type (monophasic or biphasic) and outcomes. Results: Among 5,628 pediatric out-of-hospital cardiac-arrest patients (1 through 17 years old), 430 who received defibrillation shock with monophasic or biphasic defibrillator were analyzed. The number of patients who received defibrillation shock with monophasic defibrillator was 127 (30%), and 303 (70%) received defibrillation shock with biphasic defibrillator. The survival rates at 1 month with minimal neurologic impairment were 17.5% and 24.4%, the survival rates at 1 month were 32.3% and 35.6%, and the rates of return of spontaneous circulation before hospital arrival were 24.4% and 27.4% in the monophasic and biphasic defibrillator groups, respectively. Hierarchic logistic regression analyses by using generalized estimation equations found no significant difference between the two groups in terms of 1-month survival with minimal neurologic impairment (odds ratio (OR), 1.57; 95% confidence interval (CI), 0.87 to 2.83; P = 0.14) and 1-month survival (OR, 1.38; 95% CI, 0.87 to 2.18; P = 0.17). Conclusions: The present nationwide population-based observational study could not confirm an advantage of biphasic over monophasic defibrillators for pediatric OHCA patients.
  • Soichi Koike, Seizan Tanabe, Toshio Ogawa, Manabu Akahane, Hideo Yasunaga, Hiromasa Horiguchi, Shinya Matsumoto, Tomoaki Imamura
    RESUSCITATION 82(7) 863-868 2011年7月  査読有り
    Aim: We sought to examine whether the outcomes of out-of-hospital cardiopulmonary arrest (OHCA) patients differed between weekday and weekend/holiday admissions, or between daytime and nighttime admissions. Methods: From a national registry of OHCA events in Japan between 2005 and 2008, 173,137 cases where the call-to-hospital admission interval was shorter than 120 min and collapse was witnessed by a bystander were included in this study. One-month survival rate and neurologically favourable 1-month survival rate were used as outcome measures. Logistic regression was used to adjust for potential confounding factors. Results: No significant differences in outcome were found between weekday and holiday/weekend admissions in rates of 1-month survival or neurologically favourable 1-month survival (p = 0.78 and p = 0.80, respectively). In contrast, patients admitted in the daytime exhibited significantly better outcomes than those admitted at night, on both outcome measures (p &lt; 0.001 and p &lt; 0.001). After adjusting for possible confounding factors, outcomes were significantly better for daytime admissions, with odds ratios of 1.26 (95% confidence interval (CI) 1.22-1.31; p &lt; 0.001) for 1-month survival, and 1.26 (95% CI 1.20-1.32; p &lt; 0.001) for neurologically favourable 1-month survival. In contrast, no significant differences on either outcome measure were found between weekday and weekend/holiday cases, with odds ratios of 1.00 (95% CI 0.96-1.04; p = 0.96) for 1-month survival and 0.99 (95% CI 0.94-1.04; p = 0.78) for neurologically favourable 1-month survival. Conclusions: Even after adjusting for confounding factors, admission day (weekday vs. weekend/holiday) had no effect on 1-month survival or neurologically favourable 1-month survival. In contrast, daytime admission was associated with significantly better outcomes than nighttime admissions. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
  • Soichi Koike, Seizan Tanabe, Toshio Ogawa, Manabu Akahane, Hideo Yasunaga, Hiromasa Horiguchi, Shinya Matsumoto, Tomoaki Imamura
    PREHOSPITAL EMERGENCY CARE 15(3) 393-400 2011年7月  査読有り
    Objectives. This study aimed to determine whether short cardiopulmonary resuscitation (CPR) by emergency medical services before defibrillation (CPR first) has a better outcome than immediate defibrillation followed by CPR (shock first) in patients with ventricular fibrillation/pulseless ventricular tachycardia (VF/pulseless VT) out-of-hospital cardiac arrest. Methods. We analyzed a national database between 2006 and 2008, and included patients aged 18 years or more who had witnessed cardiac arrests and whose first recorded rhythm was VF/pulseless VT. Those study subjects were divided into five groups in accordance with the CPR/defibrillation intervention sequence. Each group was subdivided into call-to-response intervals of &lt; 5 minutes and &gt;= a parts per thousand yen5 minutes. We identified 267 patients in the shock-first group and 6,407 patients in the CPR-first group. One-month survival and neurologically favorable one-month survival rates were used for outcome measures. The association of intervention type on outcomes (one-month survival or neurologically favorable one-month survival) was analyzed using multivariate logistic regression analyses by adjusting potential confounding factors such as survey year, gender, age (years), bystander CPR, intubation, and call-to-response interval (min). Results. The overall one-month survival rate was 26.2%% (3,125/11,941) and the neurologically favorable one-month survival rate was 16.6%% (1,983/11,934). The CPR-first group had a one-month survival rate of 27.8%% (1,780/6,407) and a neurologically favorable one-month survival rate of 17.8%% (1,140/6,404), and the shock-first group had survival rates of 24.7%% (66/267) and 18.4%% (49/267), respectively. There were no significant differences in one-month survival and neurologically favorable one-month survival in these two primary comparison groups (odds ratio [[95%% confidence interval]], 0.85 [[0.64--1.13]] and 1.04 [[0.76--1.42]], respectively). Logistic regression analysis showed that neither CPR first nor shock first was associated with the rate of one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders. Conclusions. In our study, CPR prior to attempted defibrillation did not present a better outcome compared with shock first as measured by either one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders. Further studies are required to determine whether CPR first has an advantage over shock first.
  • Manabu Akahane, Toshio Ogawa, Soichi Koike, Seizan Tanabe, Hiromasa Horiguchi, Tatsuhiro Mizoguchi, Hideo Yasunaga, Tomoaki Imamura
    AMERICAN JOURNAL OF MEDICINE 124(4) 325-333 2011年4月  査読有り
    OBJECTIVE: We examined the effects of sex on out-of-hospital cardiac arrest outcomes. There is evidence that women are more likely to survive cardiac arrest than men. However, few large studies have examined these sex differences in detail. It is unknown whether the female survival advantage is age-specific or whether sex affects neurologic outcomes after cardiac arrest events. METHODS: Data were analyzed from a nationwide population-based out-of-hospital cardiac arrest database (between January 2005 and December 2007) involving 318,123 patients (male: 188,357, female: 129,766) to assess the effects of sex on out-of-hospital cardiac arrest outcomes in Japan. We selected 276,590 patients aged 20 to 89 years with out-of-hospital cardiac arrest and compared the frequencies of initial cardiac rhythms, 1-month survival rates, and favorable neurologic outcome rates between sexes. RESULTS: The incidence of out-of-hospital cardiac arrest was higher in men than in women (men: 0.12%; women: 0.07%). Men were witnessed more often while out-of-hospital cardiac arrest was occurring (men: 42.1% and women: 36.9%), typically presented with initial ventricular fibrillation/ventricular tachycardia rhythms, and had a higher 1-month survival rate overall after out-of-hospital cardiac arrest events (men: 5.2% and women: 4.3%). However, the rate of survival with a favorable neurologic outcome for women aged 30 to 49 years was significantly higher than that for men within the same age range. Among patients initially presenting with ventricular fibrillation/ventricular tachycardia, the rate of survival with favorable neurologic outcome was higher for women than men in the group aged 40 to 59 years. CONCLUSION: Our results suggest that men have a higher 1-month survival rate after out-of-hospital cardiac arrest because of a higher frequency of ventricular fibrillation/ventricular tachycardia presentation compared with women. Although patients of both sexes with out-of-hospital cardiac arrest initially presenting with ventricular fibrillation/ventricular tachycardia exhibited similar overall survival rates, the rate of survival with favorable neurologic outcome was significantly higher for women than men in the group aged 40 to 59 years. (C) 2011 Elsevier Inc. All rights reserved. The American Journal of Medicine (2011) 124, 325-333
  • Hideo Yasunaga, Hiroaki Miyata, Hiromasa Horiguchi, Seizan Tanabe, Manabu Akahane, Toshio Ogawa, Soichi Koike, Tomoaki Imamura
    INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS 10 26 2011年4月  査読有り
    Background: Little is known about the effects of geographic variation on outcomes of out-of-hospital cardiac arrest (OHCA). The present study investigated the relationship between population density, time between emergency call and ambulance arrival, and survival of OHCA, using the All-Japan Utstein-style registry database, coupled with geographic information system (GIS) data. Methods: We examined data from 101,287 bystander-witnessed OHCA patients who received emergency medical services (EMS) through 4,729 ambulatory centers in Japan between 2005 and 2007. Latitudes and longitudes of each center were determined with address-match geocoding, and linked with the Population Census data using GIS. The endpoints were 1-month survival and neurologically favorable 1-month survival defined as Glasgow-Pittsburgh cerebral performance categories 1 or 2. Results: Overall 1-month survival was 7.8%. Neurologically favorable 1-month survival was 3.6%. In very low-density (&lt;250/km(2)) and very high-density(&gt;= 10,000/km(2)) areas, the mean call-response intervals were 9.3 and 6.2 minutes, 1-month survival rates were 5.4% and 9.1%, and neurologically favorable 1-month survival rates were 2.7% and 4.3%, respectively. After adjustment for age, sex, cause of arrest, first aid by bystander and the proportion of neighborhood elderly people &gt;= 65 yrs, patients in very high-density areas had a significantly higher survival rate (odds ratio (OR), 1.64; 95% confidence interval (CI), 1.44 - 1.87; p &lt; 0.001) and neurologically favorable 1-month survival rate (OR, 1.47; 95% CI, 1.22 - 1.77; p &lt; 0.001) compared with those in very low-density areas. Conclusion: Living in a low-density area was associated with an independent risk of delay in ambulance response, and a low survival rate in cases of OHCA. Distribution of EMS centers according to population size may lead to inequality in health outcomes between urban and rural areas.

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書籍等出版物

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共同研究・競争的資金等の研究課題

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