Short-term outcomes of laparoscopic and robotic distal gastrectomy for gastric cancer: Real-world evidence from a large-scale inpatient database in Japan.

BACKGROUND AND OBJECTIVES: Robotic distal gastrectomy (RDG) has been widely performed throughout Japan since it became insured in 2018. This study aimed to evaluate the short-term outcomes of RDG and laparoscopic distal gastrectomy (LDG) for gastric cancer using real-world data. METHODS: A total of 4161 patients who underwent LDG (n = 3173) or RDG (n = 988) for gastric cancer between April 2018 and October 2022 were identified through the Japanese Diagnosis Procedure Combination Database, which covers 42 national university hospitals. The primary outcome was postoperative in-hospital mortality rate. The secondary outcomes were postoperative complication rates, time to diet resumption, and postoperative length of stay (LOS). RESULTS: In-hospital mortality and postoperative complication rates in the RDG group were comparable with those in the LDG group (0.1% vs. 0.0%, p = 1.000, and 8.7% vs. 8.2%, p = 0.693, respectively). RDG was associated with a longer duration of anesthesia (325 vs. 262 min, p < 0.001), similar time to diet resumption (3 vs. 3 days, p < 0.001), and shorter postoperative LOS (10 vs. 11 days, p < 0.001) compared with LDG. CONCLUSIONS: RDG was performed safely and provided shorter postoperative LOS, since it became covered by insurance in Japan.

Comparison of inflammatory bowel disease relapse after top-down or step-up therapy: a population-based cohort study.

PURPOSE: The therapeutic effect of top-down therapy for inflammatory bowel disease (IBD) has not been fully evaluated in real-world clinical settings. We compared the effectiveness of top-down and step-up therapies for IBD. METHODS: We retrospectively evaluated patients who were admitted with IBD (Crohn's disease [CD] or ulcerative colitis [UC]) between 2012 and 2019 using the nationwide Japan Diagnosis Procedure Combination database. Patients who received immunomodulators or biologic agents at the start of observation were assigned to the top-down group and those who did not were enrolled in the step-up group. Relapse was the primary outcome, a composite outcome defined as surgery, new steroid or immunomodulator use, hospitalization, a new biologic agent, or switching biologic agents. RESULTS: We analyzed 6715 patients (CD, N = 3643; UC, N = 3072). Relapse occurred in 1982 CD cases (54.4%). The cumulative CD relapse incidence was 32.9% at 1 year and 61.3% at 5 years in the top-down group and 30.7% at 1 year and 58.6% at 5 years in the step-up group. Relapse occurred in 2032 UC cases (47.8%). The cumulative relapse incidence was 33.5% at 1 year and 50.0% at 5 years in the top-down group and 35.2% at 1 year and 51.6% at 5 years in the step-up group. No clinical factors associated with relapse were identified in patients with CD or UC. CONCLUSION: Compared with step-up therapy, top-down therapy was not associated with a decreased relapse risk in a real-world population of patients with CD or UC.

[Current issues in access to care services for the elderly in Japan focusing on special permanent residents and foreign-born Japanese: A report by the Monitoring Report Committee of the Japanese Society of Public Health].

　Japan is currently one of the countries with a long life expectancy, in which a great number of older people need care for their daily living. Japan has become increasingly internationalized due to an increase in foreigners and international marriages. As the number of elderly foreigners and foreign-born Japanese increase, older adults who do not use Japanese as their first language will need more opportunities to receive care.　We examined characteristics such as country of origin, language spoken, lifestyle, living environment, and cultural background of elderly people who were either foreign permanent residents living in Japan or foreign-born Japanese (hereinafter referred to as elderly with an international background, in short, EIB) receiving care support. Ichushi-web, a medical literature database, was used [last search date: June 2, 2018]. These searches extracted 205 papers. After the first and second extraction procedures, only two papers matched this theme. These two reports were for Korean residents in Japan, so-called special permanent residents, and repatriates from China and their spouses, many of whom were aged 75 years old and above.　The number of permanent residents in Japan who speak a foreign language as their first language is increasing. Inhibition of communication between EIB and healthcare welfare service providers is expected to be an obstacle while accessing care support services. For this reason, we must provide them with information related to Japanese healthcare services. Medical interpretation efforts are scattered and the response to EIB in the event of disasters has been discussed. From the perspective of multicultural coexistence, it is necessary to provide long-term care insurance services and medical services to EIB. Such efforts may include development and sharing of tools and the placement of staff who can communicate with non-Japanese speakers. Staff must also understand various illness- and health awareness-related issues.　In the future, considering the increasing number of EIB who may require care services, we must consider cultural backgrounds and language diversification for EIB. These issues require clarification and development of acceptable solutions.

Survival analysis of increases in care needs associated with dementia and living alone among older long-term care service users in Japan.

BACKGROUND: Japan is known for its long life expectancy and rapidly aging society that there are various demands of older adults need to be fulfilled with, and one of them is long-term care needs. Therefore, Japan implemented the Long-Term Care Insurance in year 2000 for citizens who are above 65-year old and citizens who are above 40-year old in needs of long-term care services. This study was undertaken to longitudinally examine the influence of dementia and living alone on care needs increases among older long-term care insurance service users in Japan. METHODS: Long-term care insurance claims data were used to identify enrollees who applied for long-term care services between October 2010 and September 2011, and subjects were tracked until March 2015. A Kaplan-Meier survival analysis was conducted to examine increases in care needs over time in months. Cox regression models were used to examine the effects of dementia and living alone on care needs increases. RESULTS: The cumulative survival rates before care needs increased over the 4.5-year observation period were 17.6% in the dementia group and 31.9% in the non-dementia group. After adjusting for age, sex, care needs level, and status of living alone, the risk of care needs increases was found to be 1.5 times higher in the dementia group. Living alone was not a significant risk factor of care needs increases, but people with dementia who lived alone had a higher risk of care needs increases than those without dementia. CONCLUSION: Dementia, older age, the female sex, and lower care needs levels were associated with a higher risk of care needs increases over the study period. Among these variables, dementia had the strongest impact on care needs increases, especially in persons who lived alone.

Regional variations in in-hospital mortality, care processes, and spending in acute ischemic stroke patients in Japan.

BACKGROUND: Little is known about the regional variations in ischemic stroke care in Japan. This study investigates the regional variations and associations among outcomes, care processes, spending, and physician workforce availability in acute ischemic stroke care. METHODS: Using administrative claims data from National Claims Database, we identified National Health Insurance beneficiaries aged 65 years and older and Long Life Medical Care System beneficiaries from 9 prefectures who had been hospitalized for acute ischemic stroke between April 2010 and March 2012. Patients were grouped according to their subprefectural regions of residence known as secondary medical areas (SMAs). Performances in 8 outcome and process of care measures were analyzed in each SMA. Multilevel regression models with 2 levels (patient and regional) were used to analyze age- and sex-adjusted in-hospital mortality, hospitalization spending, and tissue plasminogen activator (tPA) utilization rate. The associations between regional supply of physicians for stroke care and the various quality measures were investigated. RESULTS: We analyzed 49,440 acute ischemic stroke patients. The regional variations among SMAs in in-hospital mortality, spending, and tPA utilization were 3.2-, 1.7-, and 5.9-fold, respectively. Higher physician supply was significantly associated with lower in-hospital mortality and higher spending. Additionally, spending had a significantly negative correlation with regional continuity of care planning rate but a significantly positive correlation with rehabilitation rate. CONCLUSIONS: The study revealed substantial regional variations in Japanese ischemic stroke care. Improving the allocative efficiency of physicians and establishing continuity of care networks may be useful in mitigating regional disparities and reconstructing the stroke care system.

Association of healthcare expenditures with aggressive versus palliative care for cancer patients at the end of life: a cross-sectional study using claims data in Japan.

BACKGROUND: End-of-life (EOL) care imposes heavy economic burdens on patients and health insurers. Little is known about the association between the types of EOL care and healthcare costs for cancer patients across various providers. OBJECTIVE: To explore the association of healthcare expenditures with benchmarking indicators of aggressive versus palliative care among terminally ill cancer patients, from the perspective of health insurers. DESIGN: Cross-sectional retrospective study using health insurance claims data. SETTING: participants Cancer patients who had died in Kyoto prefecture, Japan, between April 2009 and May 2010. Main outcome measure Claims data were analyzed using multilevel generalized linear models to examine whether aggressive care and palliative care were associated with expenditures during the last 3 months of life, after adjusting for patient characteristics, hospital characteristics and other non-indicator procedures. RESULTS: We analyzed 3143 decedents from 54 hospitals. Median expenditure per patient during the last 3 months was US$13 030. Higher expenditures were associated with the aggressive care indicators of higher mortality at acute-care hospitals and use of chemotherapy in the last month of life, as well as with the palliative care indicators of increased hospice care and opioid use in the last 3 months of life. However, increased physician home care in the last 3 months was associated with lower expenditure. CONCLUSIONS: Indicators of both aggressive and palliative EOL care were associated with higher healthcare expenditures. These results may support the coherent development of measures to optimize aggressive care and reduce the financial burdens of terminal cancer care.

Factors associated with the administration of tissue plasminogen activator for acute ischemic stroke.

BACKGROUND: The use of intravenous tissue plasminogen activator (t-PA) can be an effective treatment for acute ischemic stroke if administered promptly. Despite its clinical effectiveness, overall use in Japan remains low, and regional variations have been reported. Factors such as ambulance utilization and geographical distance from patients' residences to hospitals may influence t-PA administration rates. The aim of this study is to identify factors associated with the administration of t-PA for acute ischemic stroke while adjusting for casemix using a large-scale administrative database in Japan. METHODS: We analyzed acute ischemic stroke patients admitted to acute care hospitals between July 2010 and March 2011 using a nationwide database. A logistic regression model was used to analyze the factors influencing t-PA administration. Candidate factors included patient gender, age, stroke severity, direct distance between each patient's residence and admitting hospital, and ambulance utilization. RESULTS: Of the 10,615 ischemic stroke patients from 89 hospitals analyzed, 557 (5.2%) received t-PA treatment. Patients aged 75 years and older were found to be associated with decreased t-PA administration. In contrast, severe stroke and ambulance utilization were associated with increased t-PA administration. Distance was not significantly associated with the use of t-PA. CONCLUSIONS: Our findings suggest that ambulance utilization is an important factor for improving the likelihood of t-PA administration in patients with stroke and may underline a need for educational programs to the general public that promote the use of ambulances for suspected stroke patients.

Derivation and validation of in-hospital mortality prediction models in ischaemic stroke patients using administrative data.

BACKGROUND: Stroke and other cerebrovascular diseases are a major cause of death and disability. Predicting in-hospital mortality in ischaemic stroke patients can help to identify high-risk patients and guide treatment approaches. Chart reviews provide important clinical information for mortality prediction, but are laborious and limiting in sample sizes. Administrative data allow for large-scale multi-institutional analyses but lack the necessary clinical information for outcome research. However, administrative claims data in Japan has seen the recent inclusion of patient consciousness and disability information, which may allow more accurate mortality prediction using administrative data alone. The aim of this study was to derive and validate models to predict in-hospital mortality in patients admitted for ischaemic stroke using administrative data. METHODS: The sample consisted of 21,445 patients from 176 Japanese hospitals, who were randomly divided into derivation and validation subgroups. Multivariable logistic regression models were developed using 7- and 30-day and overall in-hospital mortality as dependent variables. Independent variables included patient age, sex, comorbidities upon admission, Japan Coma Scale (JCS) score, Barthel Index score, modified Rankin Scale (mRS) score, and admissions after hours and on weekends/public holidays. Models were developed in the derivation subgroup, and coefficients from these models were applied to the validation subgroup. Predictive ability was analysed using C-statistics; calibration was evaluated with Hosmer-Lemeshow χ(2) tests. RESULTS: All three models showed predictive abilities similar or surpassing that of chart review-based models. The C-statistics were highest in the 7-day in-hospital mortality prediction model, at 0.906 and 0.901 in the derivation and validation subgroups, respectively. For the 30-day in-hospital mortality prediction models, the C-statistics for the derivation and validation subgroups were 0.893 and 0.872, respectively; in overall in-hospital mortality prediction these values were 0.883 and 0.876. CONCLUSIONS: In this study, we have derived and validated in-hospital mortality prediction models for three different time spans using a large population of ischaemic stroke patients in a multi-institutional analysis. The recent inclusion of JCS, Barthel Index, and mRS scores in Japanese administrative data has allowed the prediction of in-hospital mortality with accuracy comparable to that of chart review analyses. The models developed using administrative data had consistently high predictive abilities for all models in both the derivation and validation subgroups. These results have implications in the role of administrative data in future mortality prediction analyses.

Burden of household environmental tobacco smoke on medical expenditure for Japanese women: a population-based cohort study.

BACKGROUND: The economic consequences of environmental tobacco smoke (ETS) have been simulated using models. We examined the individual-level association between ETS exposure and medical costs among Japanese nonsmoking women. METHODS: This population-based cohort study enrolled women aged 40 to 79 years living in a rural community. ETS exposure in homes at baseline was assessed with a self-administered questionnaire. We then collected health insurance claims data on direct medical expenditures from 1995 through 2007. Using generalized linear models with interaction between ETS exposure level and age stratum, average total monthly expenditure (inpatient plus outpatient care) per capita for nonsmoking women highly exposed and moderately exposed to ETS were compared with expenditures for unexposed women. We performed separate analyses for survivors and nonsurvivors. RESULTS: We analyzed data from 4870 women. After adjustment for potential confounding factors, survivors aged 70 to 79 who were highly exposed to ETS incurred higher expenditures than those who were not exposed. We found no significant difference in expenditures between moderately exposed and unexposed women. Total expenditures were not significantly associated with ETS exposure among survivors aged 40 to 69 or nonsurvivors of any age stratum. CONCLUSIONS: We calculated individual-level excess medical expenditures attributable to household exposure to ETS among surviving older women. The findings provide direct evidence of the economic burden of ETS, which is helpful for policymakers who seek to achieve the economically attractive goal of eliminating ETS.

Widening disparity in the geographic distribution of pediatricians in Japan.

BACKGROUND: The shortage of physicians in Japan is a serious concern, particularly in specialties like pediatrics. The purpose of this study was to investigate recent changes in the geographic distribution of pediatricians and the factors underlying this change. METHODS: We investigated the numerical changes in the pediatrician workforce (2002 to 2007) per 100,000 of the population under the age of 15 years in 369 secondary medical areas throughout Japan, using attributive variables such as population size, social and economic status, and pediatric service delivery. We performed principal component analysis and multiple regression analysis. RESULTS: We obtained two principal components: one that reflected the degree of urbanization and another that reflected the volume of pediatric service delivery. Only the first component score was positively correlated with an increased pediatrician workforce per 100,000 of the population under the age of 15 years. We classified the secondary medical areas into four groups using component scores. The increase in pediatrician workforce during this period was primarily absorbed into the two groups with higher levels of urbanization, whereas the two rural groups exhibited little increase. Pediatricians aged 50 to 59 years increased in all four groups, whereas pediatricians aged 30 to 39 years decreased in the two rural groups and increased in the two urban groups. CONCLUSIONS: The trends of the pediatrician workforce increase generally kept pace with urbanization, but were not associated with the original pediatrician workforce supply. The geographic distribution of pediatricians showed rapid concentration in urban areas. This trend was particularly pronounced among female pediatricians and those aged 30 to 39 years. Given that aging pediatricians in rural areas are not being replaced by younger doctors, these areas will likely face new crises when senior physicians retire.

Comparison of Short-term Outcomes Between Esophageal Bypass Surgery and Self-expanding Stent Insertion in Esophageal Cancer: A Propensity Score-matched Analysis Using a Large-scale Inpatient Database.

BACKGROUND: Advanced esophageal cancer is occasionally accompanied by difficulty swallowing owing to esophageal stenosis or tracheoesophageal fistula formation. Esophageal bypass surgery and stent insertion are considered feasible palliative management options. The aim of this study was to evaluate the short-term outcomes of these palliative treatments. MATERIALS AND METHODS: Patient data were obtained from a large-scale inpatient database of 42 National University Hospitals in Japan. Patients with advanced esophageal cancer who underwent esophageal bypass surgery or stent insertion between April 2016 and March 2021 were included in this study. One-to-one propensity score matching of patients who underwent bypass surgery or stent insertion was performed. The primary outcomes were time to diet resumption and length of hospital stay after surgery. The secondary outcome was the incidence of postoperative complications. RESULTS: In 43 propensity score-matched pairs, the incidence of postoperative respiratory complications was significantly higher in the bypass group than in the stent group (32.6% vs. 9.3%, P = 0.008). Postoperative length of hospital stay was longer in the bypass group than in the stent group (24 vs. 10 d, P < 0.001). Logistic regression analysis revealed that stent insertion was associated with a decreased risk of respiratory complications (odds ratio 0.077, P < 0.007). Among patients who underwent the interventions (bypass surgery or stent insertion) and subsequently underwent anticancer therapy (chemotherapy/radiotherapy) during hospitalization, the interval between the intervention and anticancer therapy was longer in the bypass group than in the stent group (25 vs. 7 d, P = 0.003). CONCLUSIONS: Esophageal stent insertion provides better short-term outcomes than bypass surgery in patients with advanced unresectable esophageal cancer.

[Readmission rate for health care delivery system assessment].

OBJECTIVES: The health care system in Japan has undergone major changes, with increasing focus on specialization and continuity of care in its organization and delivery. Reducing the average length of stay is central to this plan. Readmission is often seen as an avoidable consequence of early discharges. And therefore, the readmission rate is used to assess the quality and efficiency of care. In this study, the main subjects in the implementation of readmission rate as an indicator are laid out and the framework for readmission in acute myocardial infarction (AMI) patients is applied. METHODS: Literature review concerning readmission in AMI patients was conducted to understand the key points of the framework of the readmission. We then used insurance claims data to implement readmission as an indicator. The study sample consisted of 2,332 patients hospitalized due to AMI in Kyoto Prefecture from April 2009 to March 2010. RESULTS: The 30-day readmission rate after AMI discharge was 3.7% (87/2,332), with the majority of these admissions due to coronary disease (38%). This rate was extremely low compared to the results reported in other countries, with readmission rates as high as 20% observed in the US. However, we observed that countries with high readmission rates had correspondingly short lengths of stay (LOS), and countries such as Germany and Japan with low readmission rates had long LOS. CONCLUSIONS: The readmission rate in Japan is low compared with those in other countries although mean LOS is long. The use of readmission rate may have applications in understanding trends in healthcare quality as Japan attempts to reduce LOS durations.

Comparison of Clinical Outcomes and Safety Between Open and Laparoscopic Surgery for Adhesive Small Bowel Obstruction: A Propensity-Matched Analysis of a National Inpatient Database.

Background: The effectiveness of laparoscopic surgery for adhesive small bowel obstruction (ASBO) remains unclear. We aimed to compare the outcomes and safety of open and laparoscopic surgeries for ASBO. Methods: In this retrospective study, we analyzed an inpatient database of 42 national university hospitals in Japan. Patients who underwent surgery for the first episode of ASBO between April 2013 and March 2018 were identified. Using the propensity score method, patients who underwent laparoscopic surgery were matched one-to-one with those who underwent open surgery. We investigated postoperative clinical outcomes, including morbidity, mortality, length of hospital stay (LOS), and recurrence. Results: Overall, 306 and 96 patients underwent open and laparoscopic surgery, respectively (96 propensity score-matched pairs). The incidence rates of postoperative morbidity, mortality, and recurrence were comparable between the two groups. Cox regression analysis revealed a hazard ratio (HR) of 1.020 (P = .959) for readmission due to ASBO in the laparoscopic surgery group relative to the open surgery group. Postoperative hospital stay was longer for open surgery than for laparoscopic surgery (13.0 days versus 10.0 days, P < .001). Cox regression analysis revealed that laparoscopic surgery was associated with earlier postoperative discharge compared with open surgery (HR 1.641, P = .002). Conclusions: The postoperative LOS was shorter with laparoscopic surgery than with open surgery for ASBO, but there were no differences between the procedures in other clinical outcomes. Laparoscopic surgery is suitable to treat patients with ASBO.

Impact of seasonal and meteorological factors on the incidence of adhesive small bowel obstruction: A large-scale study using a national inpatient database.

Aim: Whether seasonal and meteorological factors affect the incidence of adhesive small bowel obstruction (ASBO) remains unclear. This study aimed to clarify the impacts of seasonal and meteorological factors on the occurrence of ASBO. Methods: Clinical data of patients with ASBO were acquired from 42 national university hospitals in Japan, using a national inpatient database, between April 2012 and March 2020. Meteorological data were obtained from the Japan Meteorological Agency. The number of monthly admissions of patients with ASBO was compared between each of the 12 months. Daily weather variables were investigated to clarify their association with ASBO patient admissions on a total of 119 802 days (Formula for calculation: study period [2922 days] ×41 cities). Results: Overall, 4985 patients with ASBO were admitted. The number of admissions in June was smaller than that in October, November, and December (39 vs 63.5, P = .002, 39 vs 65, P = .004, and 39 vs 59.5, P = .002, respectively). Logistic regression analysis revealed that January, October, November, and December were associated with increased risk of admission compared to June (odds ratio [OR], 1.264; P = .001; OR, 1.454; P < .001; OR, 1.408; P < .001; OR, 1.330; P < .001), respectively. Regarding the weather variables, higher barometric pressure and lower humidity were associated with increased risk of admission (OR, 1.011; P < .001 and OR, 0.995; P < .001), respectively. Conclusion: The incidence of ASBO is susceptible to barometric pressure and humidity and varies monthly. These results can contribute to the prevention, early detection, and immediate and appropriate management of ASBO.

Factors associated with high-dose antipsychotic prescriptions in outpatients with schizophrenia: An analysis of claims data from a Japanese prefecture.

BACKGROUND: Antipsychotics are commonly prescribed in high doses in combination with multiple psychotropic drugs. This study focused on the high-dose antipsychotic prescriptions in patients with schizophrenia, while aiming to identify their associations with patients' characteristics and concurrent psychotropic prescriptions. METHODS: This cross-sectional study used claims data from a prefecture in Japan, between October 2014 and March 2015, to investigate antipsychotic prescriptions in adult outpatients with schizophrenia. The objective variable was the presence/absence of a high-dose prescription. The explanatory variables included sex, age (category), presence of comorbid conditions, and the use of psychiatrist's therapy. RESULTS: After exclusion, a total of 13 471 patients with schizophrenia were analyzed. The frequency of high-dose prescriptions was higher in men, with chlorpromazine-equivalent values highest in the age ranges of 45-54 and 35-44 years for men and women, respectively. Patients aged below 65 years with cerebrovascular diseases showed a decrease in high-dose prescriptions. There was a high frequency of polypharmacy psychotropic drug use in combination with a high-dose antipsychotic prescription in patients aged below 65 years. CONCLUSION: High-dose antipsychotics are often used in combination with several psychotropic agents in patients with schizophrenia. Our findings emphasize the need to evaluate the prescribing behavior of physicians to avoid high-dose antipsychotic prescriptions for improved patient care.

Examining sufficiency and equity in the geographic distribution of physicians in Japan: a longitudinal study.

OBJECTIVES: The objective of this study was to longitudinally examine the geographic distribution of physicians in Japan with adjustment for healthcare demand according to changes in population age structure. METHODS: We examined trends in the number of physicians per 100 000 population in Japan's secondary medical areas (SMAs) from 2000 to 2014. Healthcare demand was adjusted using health expenditure per capita. Trends in the Gini coefficient and the number of SMAs with a low physician supply were analysed. A subgroup analysis was also conducted where SMAs were divided into 4 groups according to urban-rural classification and initial physician supply. RESULTS: The time-based changes in the Gini coefficient and the number of SMAs with a low physician supply indicated that the equity in physician distribution had worsened throughout the study period. The number of physicians per 100 000 population had seemingly increased in all groups, with increases of 22.9% and 34.5% in urban groups with higher and lower initial physician supply, respectively. However, after adjusting healthcare demand, physician supply decreased by 1.3% in the former group and increased by 3.5% in the latter group. Decreases were also observed in the rural groups, where the number of physicians decreased by 4.4% in the group with a higher initial physician supply and 7.6% in the group with a lower initial physician supply. CONCLUSIONS: Although the total number of physicians increased in Japan, demand-adjusted physician supply decreased in recent years in all areas except for urban areas with a lower initial physician supply. In addition, the equity of physician distribution had consistently deteriorated since 2000. The results indicate that failing to adjust healthcare demand will produce misleading results, and that there is a need for major reform of Japan's healthcare system to improve physician distribution.

Prediction of pneumonia hospitalization in adults using health checkup data.

OBJECTIVES: Community-acquired pneumonia is a common cause of hospitalization, and pneumococcal vaccinations are recommended for high-risk individuals. Although risk factors for pneumonia have been identified, there are currently no pneumonia hospitalization prediction models based on the risk profiles of healthy subjects. This study aimed to develop a predictive model for pneumonia hospitalization in adults to accurately identify high-risk individuals to facilitate the efficient prevention of pneumonia. METHODS: We conducted a retrospective database analysis using health checkup data and health insurance claims data for residents of Kyoto prefecture, Japan, between April 2010 and March 2015. We chose adults who had undergone health checkups in the first year of the study period, and tracked pneumonia hospitalizations over the next 5 years. Subjects were randomly divided into training and test sets. The outcome measure was pneumonia hospitalization, and candidate predictors were obtained from the health checkup data. The prediction model was developed and internally validated using a LASSO logistic regression analysis. Lastly, we compared the new model with comparative models. RESULTS: The study sample comprised 54,907 people who had undergone health checkups. Among these, 921 were hospitalized for pneumonia during the study period. The c-statistic for the prediction model in the test set was 0.71 (95% confidence interval: 0.69-0.73). In contrast, a comparative model with only age and comorbidities as predictors had a lower c-statistic of 0.55 (95% confidence interval: 0.54-0.56). CONCLUSIONS: Our predictive model for pneumonia hospitalization performed better than comparative models, and may be useful for supporting the development of pneumonia prevention measures.

Novel lactonization of ethenetricarboxylate derivatives: intermolecular trapping of alkenes.

A novel cyclization of 1,1-diethyl 2-tert-butyl ethenetricarboxylate (1a) in the presence of a Lewis acid afforded a 5,5-dimethyl-gamma-lactone derivative 2a. The reaction process has been shown to arise from formation by trapping of isobutylene generated in situ. Lewis acid-promoted intermolecular reactions of 1,1-diethyl 2-hydrogen ethenetricarboxylate (5) and various alkenes to afford highly functionalized gamma-lactones were also developed. [reaction: see text]