Abstract Background The optimal surgical approach for knee arthroplasty remains under debate regarding reducing systemic complications. Although unicompartmental knee arthroplasty (UKA) is generally considered less invasive than total knee arthroplasty (TKA), it remains unclear whether this advantage persists across age groups. This study aimed to compare the risk of major systemic complications between UKA and TKA across age categories using a large-scale nationwide database. Methods Patients who underwent UKA or TKA between July 2010 and March 2022 were identified from the Diagnosis Procedure Combination database in Japan. The primary outcome was a composite of postoperative in-hospital death and major systemic complications requiring additional interventions. Rates of postoperative red blood cell (RBC) transfusion were also evaluated as a secondary outcome. Stabilized inverse probability of treatment weighting (IPTW) using propensity scores was applied to compare outcomes between the groups. Results The cohort included 36,235 UKA and 322,424 TKA cases. After stabilized IPTW adjustment, the composite outcome occurred less frequently after UKA than after TKA (risk ratio [RR] 0.65; 95% confidence interval [CI] 0.50–0.85; p = 0.001). The RBC transfusion rate was also reduced in the UKA group (RR, 0.09; 95% CI 0.08–0.11; p < 0.001). In subgroup analyses stratified by age (≤ 79 and ≥ 80 years), UKA was associated with a lower incidence of the composite outcome compared with TKA in patients aged ≤ 79 years (RR 0.48; 95% CI 0.34–0.68; p < 0.001), whereas no significant difference between UKA and TKA was observed among patients aged ≥ 80 years (RR 0.92; 95% CI 0.62–1.35; p = 0.670). The rate of RBC transfusion was lower in the UKA group across age groups (for ≤ 79 years, RR 0.07; 95% CI 0.05–0.09; p < 0.001; for ≥ 80 years, RR 0.12; 95% CI 0.10–0.14; p < 0.001). Conclusions RBC transfusion rates were consistently lower following UKA across age groups. While UKA was associated with fewer major systemic complications than TKA in patients aged ≤ 79 years, no such difference was observed in patients aged ≥ 80 years. In very elderly patients, careful perioperative risk assessment remains essential when considering UKA, similar to that for TKA.

Early intravenous crystalloid resuscitation is central to acute pancreatitis (AP) management; however, whether normal saline (NS) or balanced Ringer's solutions (RS) are superior for reducing mortality remains unsettled. Using the Japanese Diagnosis Procedure Combination database (July 2010–March 2022), we identified adults admitted to general medical wards with AP who had a hospital stay longer than 3 days and received sufficient fluid resuscitation within three days of admission. Patients were classified by predominant crystalloid exposure during the first three days (NS vs. RS). Propensity score matching was used to balance measured confounders and compare in-hospital mortality and total hospitalization costs between the two groups. Among 43,247 eligible patients, 1,652 (4.0

OBJECTIVE:Acute pancreatitis (AP) complicated by disseminated intravascular coagulation (DIC) is associated with high mortality. Although recombinant human soluble thrombomodulin (rTM) is commonly used in clinical practice, its association with outcomes in AP has not been established. DESIGN:A nationwide, propensity score-matched, retrospective cohort study. SETTING:The Japanese Diagnosis Procedure Combination national inpatient database. PATIENTS:Adult patients hospitalized with AP and DIC between July 2010 and March 2022, who survived at least 3 days. Patients were divided into those receiving rTM within three days of admission and those who did not. Propensity score matching compared in-hospital mortality. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:The analysis included 10,238 patients with AP and DIC, of whom 2,001 (19.5%) received rTM and 8,237 (80.5%) did not. Propensity score matching yielded 1,868 well-balanced pairs. In-hospital mortality was lower in the rTM group (15.5% [290/1,868]) compared with the non-rTM group (19.7% [368/1,868]; risk difference: -4.2%, 95% CI, -6.6% to -1.7%; risk ratio: 0.79, 95% CI, 0.69 to 0.91). CONCLUSIONS:Administration of rTM in patients with AP complicated by DIC was associated with lower in-hospital mortality.

AIM:To report the incidence, outcomes, resuscitation characteristics, and temporal trends of pediatric in-hospital cardiac arrest in Japan using nationwide administrative data. METHODS:Using a national administrative inpatient database from 2011 to 2022, we identified eligible admissions aged <18 years. In-hospital cardiac arrest (IHCA) was operationally defined as a hospitalization with recorded chest compressions. All eligible admissions served as the denominator for IHCA incidence calculations, whereas admissions with out-of-hospital cardiac arrest were excluded when identifying IHCA cases. RESULTS:Among 7,117,481 eligible admissions, 6962 hospitalizations with recorded chest compressions were identified as IHCA. The overall incidence of IHCA per 1000 admissions was 0.98 and decreased from 1.03 in 2011 to 0.86 in 2022 (P for trend = 0.009). Among IHCA hospitalizations, the median age was 1 year (interquartile range [IQR], 0-7), and 55.8% were male. The median recorded duration of chest compressions was 23 min (IQR 7-50). Adrenaline administration and tracheal intubation were recorded on the same calendar day as chest compressions in 71.0% and 61.7%, respectively. Overall survival to hospital discharge was 30.6% and increased from 25.8% in 2011 to 29.6% in 2022 (P for trend = 0.006). Among hospitals with IHCA, 70-80% managed only one or two cases annually. CONCLUSIONS:Using an administrative chest compression procedure code, we identified a declining incidence of IHCA and improving survival in Japan. These findings require cautious interpretation because case ascertainment was code-based. A national registry is needed to validate administrative case identification and better characterize resuscitation processes and outcomes.

Targeted axillary dissection (TAD) is a less invasive alternative to axillary lymph node dissection (ALND) for patients with clinically node-positive breast cancer who convert to node-negative status after neoadjuvant chemotherapy (NAC). However, the effect of preoperative ultrasound visibility of different clip types on TAD outcomes remains unclear. We conducted a single-center retrospective cohort study of patients with biopsy-proven axillary node-positive breast cancer who underwent NAC followed by TAD between August 2017 and December 2024. Two ultrasound-visible clips, the UltraCor™ Twirl™ (Twirl) and HydroMARK™, were evaluated. Outcomes included ultrasound visibility, clipped node retrieval success, localization techniques, and false-negative rate (FNR). Twenty-nine patients were included (Twirl, n = 15; HydroMARK, n = 14). Ultrasound visibility was higher with Twirl than with HydroMARK (86.7

Background:Coronary malperfusion (CM) is a life-threatening complication of acute type A aortic dissection (ATAAD) that has been associated with poor outcomes. Although overall surgical outcomes for ATAAD have improved over time, contemporary nationwide trends in mortality and the associated use of intensive care unit (ICU)-level resources among patients with CM remain incompletely characterized. Methods:We conducted a retrospective cohort study using the Japanese Diagnosis Procedure Combination database from July 2010 to March 2022. Patients who underwent emergency surgery for ATAAD on the day of admission were included. CM was defined by a diagnosis of acute myocardial infarction and/or receipt of coronary angiography and/or percutaneous coronary intervention on the day of admission. Temporal trends in in-hospital mortality were examined, and healthcare resource utilization was compared according to the presence or absence of CM. Results:Among 31,522 patients with surgically treated ATAAD, 1167 (3.7%) were classified as having CM. In-hospital mortality was substantially higher in patients with CM than in those without CM (34.3% vs 9.6%). After multivariable adjustment, CM was associated with increased in-hospital mortality after multivariable adjustment (adjusted hazard ratio, 1.80; 95% confidence interval, 1.58-2.06). Over the study period, in-hospital mortality declined significantly in patients without CM, whereas no temporal improvement was observed in those with CM. Patients with CM required substantially greater ICU-level resources, including prolonged mechanical ventilation and higher hospitalization costs. Conclusions:In this nationwide cohort of patients with surgically treated ATAAD, CM was associated with persistently poor short-term outcomes and greater ICU resource utilization, without clear improvement over time.

BACKGROUND:Nursing- and healthcare-associated pneumonia (NHCAP) refers to pneumonia occurring in nursing-home residents or individuals with frequent healthcare exposure. Although the Age, Dehydration, Respiratory Status, Orientation Disturbance, Low Blood Pressure (A-DROP) score is widely used to assess community-acquired pneumonia severity in Japan, it does not account for frailty or functional status, potentially limiting its predictive accuracy for NHCAP. This study aimed to develop an improved mortality prediction model for NHCAP. METHODS:We developed and validated a penalized logistic regression model to predict 30-day in-hospital mortality in patients with NHCAP using a nationwide Japanese inpatient database. Patients hospitalised for NHCAP between April 2018 and March 2020 were enrolled. Candidate predictors were selected based on clinical relevance. Logistic least absolute shrinkage and selection operator (LASSO) regression was employed to identify influential variables, from which the most important predictors were used to construct a risk score model (N-DROP) based on the A-DROP framework. RESULTS:The 30-day in-hospital mortality in 116,185 eligible patients was 11.7%. LASSO regression identified five variables, and three key predictors-A-DROP score, impaired oral intake, and diminished activities of daily living (ADL)-were retained for N-DROP. N-DROP assigned one point per A-DROP score increment, one point for impaired oral intake, and one or two points based on ADL dependence. N-DROP demonstrated improved discriminatory performance compared with A-DROP [C-statistic: 0.746 (95% CI 0.734-0.757) vs. 0.708 (95% CI 0.695-0.720); P < 0.001]. CONCLUSION:The novel N-DROP model improves prediction of in-hospital mortality compared with A-DROP in patients with NHCAP.

OBJECTIVE:This study examines annual trends and regional disparities in interventions and in-hospital outcomes for trisomies 18 and 13. STUDY DESIGN:We conducted a retrospective cohort study using nationwide data from 2011 to 2022. Patients with trisomies 18 and 13 admitted on the day of birth were identified. Nonsurgical and surgical intervention rates, survival to discharge, length of stay, and costs were analyzed by year and region. RESULT:This study identified 2 245 neonates with trisomy 18 (n = 1 808) and trisomy 13 (n = 437). Nonsurgical and surgical intervention rates increased annually. Between 2011 and 2022, survival to discharge rates improved from 44.5 to 57.9%, and both hospital length of stay and costs nearly doubled. Regional disparities in survival to discharge rates were significant, with differences of up to 21.5%. CONCLUSION:We observed an increase in interventions and a corresponding improvement in survival to discharge, with significant regional variations.

Background:In Japan, many secondary medical areas (SMAs), defined as regional self-sufficient inpatient-care planning units, are not equipped with intensive care unit (ICU) beds. We aimed to describe the national distribution of SMAs without ICUs, compared post-arrival outcomes among ICU-admitted patients, and evaluated ICU access and mortality among critically ill patients. Methods:This retrospective cohort study linked data from the Diagnosis Procedure Combination database with the Hospital Bed Function Report of 2022. The primary exposure was residence in an SMA without ICU beds. Outcomes were assessed using multivariate generalized linear models. Findings:Among 335 SMAs, 140 (41.8%) lacked ICU beds, encompassing 11.6% of the national population and 46.0% of the land area. Among the 282,894 ICU-admitted patients, residents of SMAs without ICUs travelled substantially farther to reach an ICU (median 32.4 vs. 5.7 km), but had no statistically significant difference in adjusted in-hospital mortality (adjusted risk difference, -0.38 percentage points; 95% confidence interval [CI], -0.81 to 0.05). In a separate analysis of 467,200 critically ill patients, those living in SMAs without ICUs had lower ICU admission rates (24.9% vs. 35.6%) and statistically significant but small increase in adjusted in-hospital mortality (adjusted risk difference +0.96 percentage points; 95% CI: 0.17-1.75). Interpretation:Nearly half of SMAs lack ICU beds. While post-arrival ICU outcomes were similar, residence in an SMA without ICUs was associated with reduced ICU access and higher mortality among critically ill patients. Funding:Ministry of Health, Labor and Welfare, Japan; and Japan Agency for Medical Research and Development.

BACKGROUND:Postoperative midgut volvulus is a life-threatening complication after the Ladd procedure. An adhesion barrier to prevent postoperative small-bowel obstruction could increase postoperative midgut volvulus incidence due to reduced adhesions. We aimed to examine the effect of adhesion barrier use during Ladd procedures on postoperative midgut volvulus and postoperative small-bowel obstruction. STUDY DESIGN:We retrospectively identified patients younger than 18 years who underwent the Ladd procedure between July 2010 and March 2021, using a Japanese nationwide inpatient database. We used propensity score overlap-weighting analyses to compare reoperation for midgut volvulus, rehospitalization, and operation for small-bowel obstruction, mortality, total rehospitalization length, and total rehospitalization cost within 1 year after the Ladd procedure between patients in whom adhesion barrier was used (barrier group) and patients in whom it was not used (nonbarrier group). RESULTS:Of the 1,159 eligible patients, adhesion barrier was used in 314 and not used in 845 patients. The proportion of reoperations for midgut volvulus did not differ between the barrier and nonbarrier groups (3.5% vs 2.7%; risk difference 0.8%, 95% CI -1.9 to 3.5). The proportion of rehospitalization due to small-bowel obstruction was lower in the barrier group than in the nonbarrier group (2.6% vs 6.3%; risk difference -3.6%, 95% CI -6.6 to -0.8). No significant differences were observed in operation for small-bowel obstruction, mortality, and total length and cost of rehospitalization. CONCLUSIONS:The use of adhesion barrier during the Ladd procedure can prevent rehospitalization due to postoperative small-bowel obstruction without increasing the incidence of postoperative midgut volvulus.

BACKGROUND:Despite strong recommendations for pulmonary rehabilitation in stable idiopathic pulmonary fibrosis, its efficacy during acute exacerbation (AE-IPF) remains unclear. This study aimed to investigate the effect of early rehabilitation on in-hospital mortality and clinical outcomes in patients with AE-IPF. METHODS:This study enrolled patients with idiopathic pulmonary fibrosis, who received high-dose methylprednisolone therapy within 4 days after admission between July 1, 2010, and March 31, 2023. Patients were categorized into the early rehabilitation group (rehabilitation initiated within 3 days after admission) and the usual care group (rehabilitation initiated ≥4 days after admission or no rehabilitation). The primary outcome was all-cause in-hospital mortality. The secondary outcomes included 28-day mortality, activities of daily living at discharge, and length of hospital stay. Using the hospital's preference for early rehabilitation as the instrumental variable, instrumental variable analysis was performed to account for unmeasured confounders. RESULTS:Of 6307 eligible patients, 1173 and 5134 were classified into the early rehabilitation and usual care groups, respectively. In the instrumental variable analysis, early rehabilitation was not significantly associated with reduced in-hospital mortality (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.55-1.10) or 28-day mortality (OR, 0.81; 95% CI, 0.56-1.17). Similarly, the two groups did not differ in terms of activities of daily living at discharge and length of hospital stay. CONCLUSIONS:The initiation of early rehabilitation was not significantly associated with reduced in-hospital mortality in patients with AE-IPF. Further prospective studies are required to validate the efficacy of early rehabilitation in this critically ill population.

BACKGROUND:Dementia increases the risk of adverse outcomes during hospitalisation, underscoring the need for system-level strategies. In 2016, Japan introduced Dementia Care Add-on 1 (DCA1), a financial incentive requiring hospitals to establish multidisciplinary dementia care teams. The short-term impact of DCA1 has been elucidated; however, its potential for medium-term to long-term benefits remains uncertain. In this study, we aimed to evaluate the medium-term to long-term impact of DCA1 on care processes and patient outcomes in older adults with dementia in acute-care hospitals. METHODS:Patients aged ≥65 years with moderate-to-severe dementia who were admitted to acute-care hospitals between April 2014 and March 2020 were identified using a nationwide inpatient database. Hospital-level propensity score matching was conducted, followed by a difference-in-differences analysis comparing identified inpatients of DCA1-certified and non-certified hospitals. Outcome measures were length of stay (LOS), activities of daily living maintenance, potentially inappropriate medication prescriptions, in-hospital fractures and home discharge. A sensitivity analysis excluding hospitals certified only for the less stringent DCA2 scheme was conducted. RESULTS:Overall, 309 791 patients from 235 matched hospital pairs were analysed. DCA1 certification was not associated with improvements in the measured outcomes. Notably, >60% of DCA1 hospitals billed for <20% of eligible patients, indicating limited and inconsistent implementation. In a restricted analysis excluding DCA2-certified hospitals, DCA1 certification showed a statistically significant reduction in LOS (change: -11.3%; 95% CI -19.8% to -3.0%). No significant associations were observed for the other outcomes. CONCLUSIONS:DCA1 was not associated with measurable improvements in patient outcomes at the certification level. However, under more homogeneous comparison conditions, an association was observed with shorter LOS. These findings show that structural certification alone may be insufficient to achieve consistent improvements in dementia care outcomes in acute hospital settings.

Abstract Background Intensive care is a cornerstone of modern health systems, yet it remains among the most resource-intensive and costly forms of care. While intensive care unit (ICU) costs represent a substantial portion of health care expenditures in many high-income countries, national-level data on ICU costs in Japan have been lacking. We aimed to estimate national ICU costs in Japan using administrative and hospital-level data, employing internationally comparable methods. Methods We conducted a nationwide retrospective cohort study using the Diagnosis Procedure Combination Study Group database and the Hospital Bed Function Report during fiscal years 2018–2022. ICU costs were estimated using a bottom-up costing approach aligned with the method used in major international studies, and focused on certified adult and pediatric ICUs. Macroeconomic impact, temporal trends, and regional variation were assessed. We also analyzed the cost of intermediate care units (IMCU) and IMCU–ICU ratio. Results A total of 1,453,929 ICU patients were identified in the DPC Study Group database from 2018 to 2022, which covers 68.2% of all ICU beds in Japan. The mean ICU cost per patient-day was ¥197,277 (approximately $1,793 USD), and the estimated national ICU cost over the 2018–2022 period was ¥1,785 billion (mean ¥357 billion per year). This represented 0.065% of nominal gross domestic product (GDP), 0.56% of total health expenditures, 1.42% of hospital expenditures, and 2.17% of inpatient expenditures. The macroeconomic impact of ICU care was stable from 2018 to 2022. The proportion of ICU costs relative to nominal GDP, total health expenditures, and hospital expenditures in Japan was substantially lower than in the United States, Canada, and Australia. Regional variation was pronounced, with up to a 7.5-fold difference across prefectures. The estimated national IMCU cost over the 2018–2022 period was ¥2,838 billion (mean ¥568 billion per year), approximately 1.5 times greater than ICU cost (IMCU–ICU ratio is approximately 1.59). Conclusions This study provides the first comprehensive national estimates of ICU costs in Japan using internationally aligned methods. These findings indicate lower ICU spending in Japan than in other high-income countries.

Background:Although docetaxel-based triplet neoadjuvant chemotherapy has yielded promising results for locally advanced esophageal cancer, there are concerns that the triplet regimen can increase perioperative adverse events in older patients. This retrospective study assessed the perioperative outcomes following doublet or docetaxel-based triplet chemotherapy and esophagectomy in older patients. Methods:The data of patients aged 70-79 years who received cisplatin and 5-fluorouracil (CF) or docetaxel, cisplatin, and 5-fluorouracil (DCF) before esophagectomy were extracted from a nationwide Japanese inpatient database (April 2012-March 2022). The primary outcomes were major and respiratory complications. The secondary outcomes included anastomotic leakage, 30-day unplanned readmission, and 30- and 90-day mortality. Analyses were conducted using overlap propensity score weighting, propensity score matching, and instrumental variable methods to adjust for potential confounders. Results:Of 5229 eligible patients, 3457 (66%) and 1772 (34%) patients received neoadjuvant CF and DCF, respectively. Major and respiratory complications occurred in 5229 (40%) and 1388 (27%) patients, respectively. After overlap weighting, DCF was not associated with a higher frequency of major (odds ratio 0.99 [95% confidence interval 0.87-1.12]) and respiratory complications (odds ratio 1.04 [0.90-1.19]) compared with CF. The frequencies of anastomotic leakage, 30-day unplanned readmission, and 30- and 90-day mortality did not differ between the groups. Propensity score matching and instrumental variable analyses yielded similar results. Conclusions:Neoadjuvant DCF was not associated with a higher frequency of perioperative adverse events compared with CF after esophagectomy in patients aged 70-79 years.

Background Data on the first-line treatment options for patients with Pneumocystis pneumonia (PCP) without human immunodeficiency virus (HIV) infection are limited. Therefore, we evaluated the outcome of pentamidine compared to trimethoprim-sulfamethoxazole (TMP-SMX) in non-HIV patients with PCP. Methods We used data from the Japanese Diagnosis Procedure Combination Inpatient Database. We included non-HIV PCP patients who initially received TMP-SMX or pentamidine between July 2010 and March 2022. We categorized eligible patients into TMP-SMX and pentamidine groups and performed a propensity score overlap weighting analysis to compare in-hospital mortality between the groups. Results Among 5,870 eligible patients, 5,456 and 414 received TMP-SMX and pentamidine, respectively. Pentamidine treatment was associated with a higher in-hospital mortality than TMP-SMX treatment in the propensity score overlap weighting analysis (23.6% vs. 40.1%; risk difference, 16.5%; 95% confidence interval, 10.8-22.2%; p<0.001). Conclusions Based on these findings, pentamidine may not be as effective as TMP-SMX for treating PCP in non-HIV patients.

Pneumocystis jirovecii pneumonia (PCP) in non-human immunodeficiency virus (HIV) patients is associated with high morbidity and mortality. Although prior studies have linked delayed treatment to worse outcomes, they are often limited by small sample sizes and inadequate adjustment for confounders. Therefore, we evaluated whether early treatment after hospital admission improves mortality in non-HIV PCP, adjusting for patient characteristics. This multi-center, retrospective, observational cohort study included non-HIV PCP patients treated between January 2006 and March 2021 at three institutions. Participants were divided into the early treatment (initiated within 2 days) and late treatment (initiated between days 3 and 7) groups. The primary endpoint was 30-day mortality, and the secondary endpoints were 180-day mortality. Propensity score weighting was used to adjust for patient background. Ninety-four patients in the early treatment group and 43 in the late treatment group were evaluated. The average time-to-treatment for the early and late treatment groups was 0.13 days and 3.63 days, respectively. After adjusting for patient characteristics, there were no significant differences in 30-day mortality (14.0

BACKGROUND:Previous studies have suggested an association between comorbid schizophrenia and various outcomes in patients with cancer, including cancer stage at admission, treatment, and in-hospital mortality. However, studies focusing specifically on patients with pancreatic cancer are limited. AIMS:This study aimed to elucidate the association between comorbid schizophrenia and cancer stage at admission, treatment, length of stay, and 30-day in-hospital mortality in patients with pancreatic cancer, while considering patient background factors, medical facilities, and year of treatment. METHOD:We conducted a retrospective matched-pair cohort study using data from the Japanese Diagnosis Procedure Combination database. Patients with pancreatic cancer and comorbid schizophrenia were matched to those without psychiatric disorders at a maximum ratio of 1:4 according to sex, age group, year of admission, and admission facility. Each matched pair was treated as a cluster, and multivariable regression analyses using generalised estimating equations were performed to evaluate the association between psychiatric comorbidities and cancer-related outcomes. RESULTS:After adjusting for patient background factors, medical facilities, and the year of treatment, patients with comorbid schizophrenia were significantly more likely to be admitted with stage IV cancer, less likely to undergo chemotherapy, and more likely to have longer hospital stays and higher 30-day in-hospital mortality than those without psychiatric disorders. Although not statistically significant, patients with schizophrenia were less likely to undergo cancer-directed surgery. CONCLUSIONS:Patients with pancreatic cancer and comorbid schizophrenia were significantly more likely to present with advanced cancer at admission, were less likely to receive chemotherapy, had longer hospital stays, and experienced higher 30-day in-hospital mortality than those without psychiatric disorders. Although not statistically significant, patients with schizophrenia were less likely to undergo cancer-directed surgery.

Heat-related diseases have become a significant public health concern. Studies have shown that susceptibility to heat varies among regions; however, most studies used aggregated data on emergency transport in the regions. The present study used a nationwide inpatient database in Japan and examined the association between regional differences in Wet Bulb Globe Temperature (WBGT) and in-hospital mortality in patients with a heat-related disease, with adjustment for individual-level characteristics. We retrospectively identified participants from the Japanese Diagnosis Procedure Combination inpatient database during the five warmest months of the year (May 1 to September 30) from 2011 to 2019. We calculated the long-term average daily maximum WBGT for the prefectures and categorized the prefectures into three areas (low-, middle-, and high-WBGT). We conduced multivariable logistic regression analyses to compare in-hospital mortality between the WBGT areas, adjusting for individual-level covariates (including age, sex, body mass index, and comorbidities). A total of 82,250 patients were admitted for heat-related diseases. The mean age was 63.2 (standard deviation, 25.0) years, and 63.7% were male. In the multivariable logistic regression analysis, the low-WBGT area had a higher in-hospital mortality than that had by the high-WBGT area (odds ratio, 1.32; 95% confidence interval, 1.15-1.52), whereas no significant difference was observed between the middle- and high-WBGT areas (odds ratio, 1.00; 95% confidence interval, 0.89-1.12). After adjusting for individual-level risk factors, in-hospital death was more likely to occur in patients with heat-related diseases in lower WBGT areas compared with those in higher WBGT areas.