Comprehensive analysis of risk factors for coronavirus disease 2019 infection and post-infection sequelae based on real-world data from a health insurance database in Japan

OBJECTIVES: Using real-world data from Japan, this study aimed to examine disease risks in COVID-19 patients before and after infection. METHODS: We used the Japanese Health Insurance Database to identify hospitalized patients in Japan aged 60 years who were newly diagnosed with COVID-19 by December 31, 2020. To form the study population, these patients were matched 1:1 with individuals without COVID-19 on the basis of age, sex, and index date. Two analytical approaches were employed: a case-control study using conditional logistic least absolute shrinkage and selection operator (LASSO) regression to identify risk factors for COVID-19 infection and a retrospective cohort study using time-to-event analysis to evaluate the risk of developing sequelae following infection. RESULTS: Overall, 8072 patients were included (4036 in each group). Organic, including symptomatic mental disorders demonstrated the strongest association (odds ratio, 2.276). Following infection, behavioral syndromes associated with physiological disturbances and physical factors exhibited the highest risk of developing new conditions (hazard ratio [HR], 3.523; 95% confidence interval [CI], 2.101-5.907), followed by pulmonary heart disease and diseases of the pulmonary circulation (HR, 2.954; 95% CI, 1.360-6.420). CONCLUSION: Our findings suggest an association between COVID-19 and mental and behavioral disorders.