Validation of recorded data is a prerequisite for studies that utilize administrative databases. The present study evaluated the validity of diagnoses and procedure records in the Japanese Diagnosis Procedure Combination (DPC) data, along with laboratory test results in the newly-introduced Standardized Structured Medical Record Information Exchange (SS-MIX) data. Between November 2015 and February 2016, we conducted chart reviews of 315 patients hospitalized between April 2014 and March 2015 in four middle-sized acute-care hospitals in Shizuoka, Kochi, Fukuoka, and Saga Prefectures and used them as reference standards. The sensitivity and specificity of DPC data in identifying 16 diseases and 10 common procedures were identified. The accuracy of SS-MIX data for 13 laboratory test results was also examined. The specificity of diagnoses in the DPC data exceeded 96%, while the sensitivity was below 50% for seven diseases and variable across diseases. When limited to primary diagnoses, the sensitivity and specificity were 78.9% and 93.2%, respectively. The sensitivity of procedure records exceeded 90% for six procedures, and the specificity exceeded 90% for nine procedures. Agreement between the SS-MIX data and the chart reviews was above 95% for all 13 items. The validity of diagnoses and procedure records in the DPC data and laboratory results in the SS-MIX data was high in general, supporting their use in future studies.

OBJECTIVES: To investigate the temporal trend in the national incidence of bronchiolitis hospitalizations, their characteristics, inpatient resource use, and hospital cost from 2000 through 2016. METHODS: We performed a serial, cross-sectional analysis of nationally representative samples (the 2000, 2003, 2006, 2009, 2012, and 2016 Kids’ Inpatient Databases) of children (age <2 years) hospitalized for bronchiolitis. We identified all children hospitalized with bronchiolitis by using International Classification of Diseases, Ninth Revision, Clinical Modification 466.1 and International Classification of Diseases, 10th Revision, Clinical Modification J21. Complex chronic conditions were defined by the pediatric complex chronic conditions classification by using inpatient data. The primary outcomes were the incidence of bronchiolitis hospitalizations, mechanical ventilation use, and hospital direct cost. We examined the trends accounting for sampling weights. RESULTS: From 2000 to 2016, the incidence of bronchiolitis hospitalization decreased from 17.9 to 13.5 per 1000 person-years in US children (25% decrease; P_trend < .001). In contrast, the proportion of bronchiolitis hospitalizations among overall hospitalizations increased from 16% to 18% (P_trend < .001). There was an increase in the proportion of children with a complex chronic condition (6%–13%; 117% increase), hospitalization to children’s hospital (15%–29%; 93% increase), and mechanical ventilation use (2%–5%; 184% increase; all P_trend < .001). Likewise, the hospital cost increased from $449 million to $734 million (63% increase) nationally (with an increase in geometric mean of cost per hospitalization [from $3267 to $4086; 25% increase; P_trend < .001] adjusted for inflation) from 2003 to 2016. CONCLUSIONS: From 2000 through 2016, the incidence of bronchiolitis hospitalizations among US children declined. In contrast, mechanical ventilation use and nationwide hospital direct cost substantially increased.

Objective To examine the incidence of vertebral osteomyelitis (VO) and the clinical features of VO focusing on risk factors for death using a Japanese nationwide administrative database. Design Retrospective observational study. Setting Hospitals adopting the Diagnosis Procedure Combination system during 2007–2010. Participants We identified 7118 patients who were diagnosed with VO (International Classification of Diseases, 10th Revision codes: A18.0, M46.4, M46.5, M46.8, M46.9, M48.9 and M49.3, checked with the detailed diagnoses in each case and all other codes indicating the presence of a specific infection) and hospitalised between July and December, 2007–2010, using the Japanese Diagnosis Procedure Combination database. Main outcome measures The annual incidence of VO was estimated. Logistic regression analysis was performed to analyse factors affecting in-hospital mortality in the VO patients. Dependent variables included patient characteristics (age, sex and comorbidities), procedures (haemodialysis and surgery) and hospital factors (type of hospital and hospital volume). Results Overall, 58.9% of eligible patients were men and the average age was 69.2 years. The estimated incidence of VO increased from 5.3/100 000 population per year in 2007 to 7.4/100 000 population per year in 2010. In-hospital mortality was 6%. There was a linear trend between higher rates of in-hospital mortality and greater age. A higher rate of in-hospital mortality was significantly associated with haemodialysis use (ORs, 10.56 (95% CI 8.12 to 13.74)), diabetes (2.37 (1.89 to 2.98)), liver cirrhosis (2.63 (1.49 to 4.63)), malignancy (2.68, (2.10 to 3.42)) and infective endocarditis (3.19 (1.80 to 5.65)). Conclusions Our study demonstrates an increasing incidence of VO, and defines risk factors for death with a nationwide database. Several comorbidities were significantly associated with higher rates of in-hospital death in VO patients.

Background and Purpose—: We aimed to examine the concurrent effects of timing and intensity of rehabilitation on improving activities of daily living (ADL) among patients with ischemic stroke. Methods—: Using the Japanese Diagnosis Procedure Combination inpatient database, we retrospectively analyzed consecutive patients with ischemic stroke at admission who received rehabilitation (n=100 719) from April 2012 to March 2014. Early rehabilitation was defined as that starting within 3 days after admission. The average rehabilitation intensity per day was calculated as the total units of rehabilitation during hospitalization divided by the length of hospital stay. A multivariable logistic regression analysis with multiple imputation and an instrumental variable analysis were performed to examine the association of early and intensive rehabilitation with the proportion of improved ADL score. Results—: The proportion of improved ADL score was higher in the early and intensive rehabilitation group. The multivariable logistic regression analysis showed that significant improvements in ADL were observed for early rehabilitation (odds ratio: 1.08; 95% confidence interval: 1.04–1.13; P 5.0 U/d (odds ratio: 1.87; 95% confidence interval: 1.69–2.07; P <0.01). The instrumental variable analysis showed that an increased proportion of improved ADL was associated with early rehabilitation (risk difference: 2.8%; 95% confidence interval: 2.0–3.4%; P <0.001) and intensive rehabilitation (risk difference: 5.6%; 95% confidence interval: 4.6–6.6%; P <0.001). Conclusions—: The present results suggested that early and intensive rehabilitation improved ADL during hospitalization in patients with ischemic stroke.

Objectives: The role of intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation in cardiogenic shock patients remains unknown. This study investigated the effect of intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation on reducing mortality of cardiogenic shock patients.Design: Retrospective cohort study.Setting: The Japanese Diagnosis Procedure Combination national inpatient database.Patients: Cardiogenic shock adult patients receiving peripheral venoarterial extracorporeal membrane oxygenation at admission were identified in the Japanese Diagnosis Procedure Combination database from July 1, 2010, to March 31, 2013.Interventions: None.Measurements and Main Results: The primary outcomes were all-cause 28-day mortality and in-hospital mortality, and the secondary outcome was the proportion of patients weaned from venoarterial extracorporeal membrane oxygenation, using propensity score matching. Eligible patients (n= 1,650) were divided into the intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation group (n= 604) and the venoarterial extracorporeal membrane oxygenation–alone group (n= 1,064). Propensity score matching created matched cohort of 533 pairs. In the propensity score–matched analysis, all-cause 28-day mortality and in-hospital mortality were significantly lower in the intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation group than the venoarterial extracorporeal membrane oxygenation–alone group (48.4% vs 58.2%;p= 0.001 and 55.9% vs 64.5%;p= 0.004, respectively). In Cox regression, there was a significant difference in survival between the intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation group and the venoarterial extracorporeal membrane oxygenation–alone group (hazard ratio, 0.74; 95% CI, 0.63–0.86;p< 0.001). The proportion of patients weaned from venoarterial extracorporeal membrane oxygenation was significantly higher in the intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation group than in the venoarterial extracorporeal membrane oxygenation–alone group (82.6% vs 73.4%;p< 0.001).Conclusions: In a national inpatient database, intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation was associated with improved mortality and successful weaning from venoarterial extracorporeal membrane oxygenation. Randomized controlled studies are required to confirm the mortality-reducing effect of intraaortic balloon pumping combined with venoarterial extracorporeal membrane oxygenation.