Journal of Epidemiology最新文献

Medical claims data are increasingly used in epidemiological studies, but are inadequately validated to ensure their reliability in identifying diseases. We developed the Claims data Learning & Enhancing for Algorithm Refinement (CLEAR) Study as a database platform to enable the systematic, low-cost implementation of validation studies in Japan. The CLEAR Study links routinely generated medical claims data from hospitals with diagnostic data (e.g., laboratory data and diagnostic imaging reports) at the patient level. Using diagnostic data as the gold standard for disease identification, researchers can validate and refine their claims-based identification algorithms. Diagnostic data are collected as needed for each validation study, and data are linked using pseudonymized medical record numbers. Personal information is protected through the use of research identification numbers. To demonstrate the platform's feasibility, we collected data on respiratory syncytial virus (RSV) infections and intussusception cases. Eight hospitals have agreed to participate in the CLEAR Study, and three have completed claims data provision. We obtained data for 5,022 RSV infection cases with 25,920 diagnostic tests, and 1,450 intussusception cases with 561,984 diagnostic tests. We also analyzed the initial diagnostic data for 39,212 RSV infection cases and 439,088 intussusception cases, demonstrating that the database can be used to validate algorithms for these diseases. The CLEAR Study is a newly developed database platform in Japan that facilitates validation studies of claims data for various diseases. By promoting validation studies, this platform will help to improve the reliability of claims-based epidemiological studies and drug risk assessments in Japan.

Background: Changes in nutritional status during the coronavirus disease 2019 (COVID-19) pandemic may be attributed to the obesity-causing environment that had existed before. This paper aimed to investigate trends in thinness, overweight, and obesity among Chinese children aged 2 to 18 years from 2010 to 2020 and assess the potential influence of pandemic.

Methods: The Chinese Family Panel Studies that were conducted every 2 years between 2010 and 2020 included 48,642 children between the ages of 2 and 18 years. Height and mass were reported, and the body mass index (BMI) was calculated. The prevalence of thinness, overweight, and obesity was estimated using sex- and age-specific BMI cut-offs adopted by the International Obesity Task Force and population-weighted procedures. Linear regressions were used to estimate trends.

Results: The prevalence of thinness decreased from 25.5% to 22.2% but increased among children aged 2 to 6 years. The prevalence of overweight and obesity decreased from 24.6% and 14.2% to 22.5% and 10.0%, respectively. However, these decreases in the prevalence of overweight and obesity were attributed mostly to children aged 2 to 6 years, and the prevalence increased slightly among children aged 13 to 18 years. The prevalence of obesity in 2020 among only boys aged 13 to 15 years was greater than the estimated projections using data from 2010 to 2018.

Conclusion: From 2010 to 2020, the prevalence of all forms of malnutrition among Chinese children decreased, with age disparities. During the pandemic, overweight became more common among pubertal boys. Future interventions as well as policies ought to give high-risk groups priority.

Background: This study aimed to describe the clinical outcomes and medical costs of hospitalized children requiring daily medical care (CRDMC), a patient group for which government-led support has developed rapidly in Japan.

Methods: A retrospective longitudinal study was conducted using a nationwide administrative database. All hospitalizations of children aged under 18 years discharged from April 2014 to March 2021 were included. Clinical outcomes and medical costs were compared between CRDMC and non-CRDMC hospitalizations. The estimated increase in the proportion of CRDMC medical costs among all pediatric hospitalizations during the study period was also calculated.

Results: Among the 1,531,456 hospitalizations included, 91,413 were identified as CRDMC. CRDMC accounted for 3.7% of the annual unique inpatients. The 30-day readmission rate among CRDMC was 27.5%, and the rate among those receiving multiple types of medical care was higher at 33.7%. The inpatient medical cost of CRDMC accounted for 20.3% of pediatric inpatient medical costs, with an estimated rise of 1.2881 (95% confidence interval, 1.2110-1.3702) during the study period. In the breakdown of the medical costs, the proportion of injection drug fees increased most rapidly.

Conclusion: The high 30-day readmission rate in CRDMC was distinctive among the clinical outcomes. The proportion of medical costs for CRDMC in pediatric inpatients was high, although CRDMC accounted for only a small proportion of annual unique inpatients. Further support for CRDMC must be based on the unique characteristics of this population.

BackgroundThe Shanghai University of Sport (SUS) Longitudinal Cohort Study (SUS Cohort) was established to investigate the influence of lifestyle and modifiable behavioural factors in early adulthood on the development of non-communicable diseases (NCDs) later in life. The cohort aims to identify novel biomarkers and explore mechanisms underlying chronic diseases using a multi-omics approach.MethodsThe SUS Cohort study is a prospective cohort study of undergraduate students between 2018 and 2019, with follow-ups conducted every two years during early adulthood and every ten years thereafter. Comprehensive data collection includes body composition measurements, lifestyle surveys, physical fitness tests, and clinical laboratory tests. Multi-omics analysis, including genome-wide genotyping, gut microbiome and serum metabolome, is integrated to provide insights into disease pathophysiology.ResultsA total of 1,758 participants aged 18 to 22(mean age: 18.64 ± 3.15) were conducted from baseline surveys, with a follow-up period between September 2021 and September 2022. The median age at baseline was 18 years, and the proportion of female participants was about 871(49.5%). Of the initial participants, 1,055 individuals (60%) completed the follow-up.ConclusionThe SUS Cohort provides multidimensional data to study how early-life factors influence long-term health outcomes.

BackgroundMedical corporations (Iryohoujin) are central to Japan's healthcare delivery, yet their financial conditions have not been comprehensively assessed nationwide. This study aimed to describe financial trends and structural characteristics of hospital-operating corporations from fiscal year (FY) 2016 to FY2022 and examine fluctuations, including during the FY2020-FY2021 COVID-19 pandemic.MethodsA longitudinal analysis was conducted using financial data covering 95% of all hospital-operating medical corporations. Financial indicators, including total assets, medical revenue, and profit margin, were tracked from FY2016 to FY2022. Subgroup analyses were based on organizational size and integration. A linear mixed-effects model examined factors associated with profitability.ResultsThe number of hospital-operating medical corporations declined from 4,631 in FY2016 to 4,469 in FY2022. By FY2022, total assets and medical revenue reached 15.9 trillion JPY and 12.5 trillion JPY. Median medical profit margin declined from 1.8% (interquartile range [IQR], -1.2% to 5.3%) in FY2016 to 0.6% (IQR, -3.4% to 4.3%) in FY2021, then recovered to 1.6% (IQR, -2.5% to 5.5%) in FY2022. Smaller corporations, with fewer hospitals and beds, were more financially unstable, especially during the COVID-19 pandemic. A linear mixed-effects model showed that medical profit margin was negatively associated with hospital number and positively associated with long-term care and psychiatric beds.ConclusionsThis study highlights the structural scale and financial dynamics of Japanese medical corporations, revealing a large but unevenly resilient sector in which not only hospital size but also bed composition significantly influences profitability. These findings may inform policy discussions on healthcare system sustainability and financial support.

Background: Researchers widely use the Diagnosis Procedure Combination (DPC) database for studies on acute-care hospitalization in Japan. However, the validity of acute kidney injury (AKI) diagnostic codes among patients who underwent surgery under general anesthesia is unclear.

Methods: Under the Japanese Next-Generation Healthcare Infrastructure Act, we obtained DPC data linked with the laboratory data of adult surgical patients with baseline and follow-up serum creatinine measurements from three hospitals (2021- 2024). Recorded diagnoses of AKI were identified using the International Classification of Diseases-10^th Revision codes (N17.x). The reference standard was the diagnosis of AKI per the creatinine-based Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The sensitivity, specificity, likelihood ratios, and predictive values were calculated. We evaluated the coding validity for identifying AKI stages 2 and 3. Subgroup analyses were conducted according to baseline estimated glomerular filtration rates (eGFR) (≥60.0, 30.0-59.9, 15.0-29.9 mL/min/1.73 m²), type of admission (planned/emergent), and surgery type (cardiovascular/non-cardiovascular).

Results: Among 7,374 eligible patients, 663 (9.0%) met the KDIGO-defined AKI criteria, while 35 (0.5%) patients had the AKI codes. The sensitivity was 4.1% (95% CI, 2.7-5.9%), and specificity was 99.9% (95% CI, 99.8-99.9%). The sensitivity increased for patients with stages 2 and 3 AKI, lower eGFR, emergent admission, or cardiovascular surgery.

Conclusions: Among surgical patients, AKI coding in the DPC exhibited high specificity and positive predictive value, albeit low sensitivity. Incorporating laboratory data is important for more accurate identification of patients with AKI for use in clinical studies.

Background: Meningococcal infection remains a life-threatening disease despite advances in early recognition and therapy. While the incidence of meningococcal infection is extremely low in Japan, nationwide data on its clinical outcomes have been lacking.

Methods: We conducted a retrospective cohort study using the Japanese Diagnosis Procedure Combination (DPC) inpatient database from July 2010 to March 2023. Patients with a main diagnosis of meningococcal infection (ICD-10 code A39) were included. The primary outcome was in-hospital mortality. Secondary outcomes included impaired consciousness at discharge and functional status, assessed by the Barthel Index. Multivariable logistic regression was performed to identify prognostic factors.

Results: A total of 465 patients were analyzed. The median age was 55 years, and 57.0% were male. The in-hospital mortality rate was 8.2%, and 40.2% of survivors had a Barthel Index ≤90 at discharge. Early antibiotic administration did not significantly reduce mortality but was associated with improved neurological outcomes. Baseline impaired consciousness was the strongest predictor of mortality and poor functional status, while chronic comorbidities also contributed to worse outcomes. Notably, older age itself was not independently associated with mortality after adjustment for severity and comorbidities.

Conclusion: Meningococcal infection outcomes in Japan are predominantly determined by the severity of illness at presentation and comorbid health conditions rather than age alone. Early antibiotic therapy improves neurological recovery but may not prevent death once critical illness is established. These findings underscore the importance of prevention through vaccination and early recognition strategies to reduce the burden of this devastating infection.