Incidence of depression in kidney transplant recipients in South Korea: a long-term population-based study

Depression is associated with impaired quality of life and increased morbidity and mortality in end-stage kidney disease (ESKD) patients and kidney transplantation (KT) recipients. Depression incidence after KT is unclear. We compared depression incidence among KT recipients, ESKD patients, and healthy controls (HCs). We analyzed a nationwide health insurance database in South Korea and identified patients who underwent KT during 2007-2015. Participants were matched for age, sex, and inclusion year. KT and ESKD patients were further matched for hypertension and diabetes mellitus history. The incidence rate (IR, per 1000 patients-years) of depression was compared among KT, ESKD, and HC groups. We analyzed 5,234 patients per group. Depression incidence was markedly lower in KT than ESKD patients (IR, 18.87 vs. 58.03; hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.30‒0.36), but only slightly higher in KT recipients than in HCs (IR, 18.87 vs. 17.49; HR, 1.08; 95% CI, 0.96‒1.22). After adjusting for comorbidities, the depression risk was lower in KT recipients than in HCs (adjusted HR, 0.52; 95% CI, 0.44‒0.62; p < 0.001), whereas it remained higher in ESKD patients than in HCs (adjusted HR, 1.60; 95% CI, 1.36‒1.87; p < 0.001). Among KT recipients, older age, female sex, lower economic status, and more comorbidities were associated with increased depression risk. Incident depression after KT increased mortality, graft failure, and death-censored graft failure risks in KT recipients. Our data suggest a broader role of KT than previously appreciated in terms of improving quality of life by reducing depression risk.