Mental disorders and subsequent kidney function decline: A nationwide cohort study in Japan.

BACKGROUND: Mental disorders are associated with multiple medical conditions, but a comprehensive assessment of their association with kidney function decline remains limited. We examined this association in a large population-based cohort. METHODS: We conducted a retrospective cohort study using nationwide claims data linked to health checkup records (April 2008-July 2024). Baseline mental disorders were defined using ICD-10 codes and categorized into 10 groups. The primary outcome encompassed three kidney events: a decrease in estimated glomerular filtration rate of at least 30% from baseline, incident end-stage kidney disease, and initiation of kidney replacement therapy. RESULTS: Among 2,989,648 individuals (median age, 45 years [IQR, 37-53]; 60.5% men), 301,715 (10.1%) had at least one mental disorder. Over a median follow-up of 1252 days (IQR, 728-1805), 31,996 individuals experienced the composite kidney outcome. In multivariable Cox models, seven of the 10 categories were significantly associated with the outcome; the highest hazard ratios (HRs) were observed for personality disorders (HR 2.37 [95% CI, 1.55-3.64]), organic disorders (HR 1.80 [95% CI, 1.41-2.31]), and eating disorders (HR 1.69 [95% CI, 1.32-2.16]). Overall, the presence of any mental disorder was associated with a higher risk of the composite outcome (HR 1.12 [95% CI, 1.09-1.16]), with greater risk observed among individuals with multiple mental disorder categories (HR 2.51 [95% CI, 1.86-3.39] for ≥4 categories). CONCLUSIONS: Most categories of mental disorders were associated with subsequent kidney function decline in this nationwide cohort, suggesting that kidney surveillance may be warranted for adults with mental disorders.