Effect of depression on progression to end‐stage renal disease or pre‐end‐stage renal disease death in advanced diabetic nephropathy: A prospective cohort study of the Diabetes Study from the Center of Tokyo Women’s Medical University

AIMS/INTRODUCTION: This study aimed to determine the effect of depression on the progression to end‐stage renal disease (ESRD) and pre‐ESRD death in patients with advanced diabetic nephropathy. MATERIALS AND METHODS: This single‐center prospective cohort study enrolled Japanese patients with type 2 diabetes and advanced diabetic nephropathy. The total Patient Health Questionnaire‐9 score was used to evaluate depression at baseline and classified patients into: no, mild and severe depression groups. The outcomes were ESRD, defined as initiation of renal replacement therapy, and pre‐ESRD death. The relationship between the severity of depression and these outcomes was analyzed using a competing risks model, defining each outcome as the competing risk of the other outcome. RESULTS: Of the 486 patients with a mean estimated glomerular filtration rate of 37.1 ± 21.1 mL/min/1.73 m(2), 345 were men. During the median follow up of 4.4 years, 164 patients progressed to ESRD and 50 died. The cumulative incidence function of ESRD was significantly higher in the severe depression group (Gray’s test, P = 0.003). The ESRD risk increased by 12.4% and 45.1% in patients with mild and severe depression, respectively, compared with those without depression, although these differences did not reach statistical significance in the multivariate subdistribution hazard model (P = 0.450 and 0.161, respectively). The cumulative incidence of death was similar for the study groups. CONCLUSION: Depression potentially has a weak impact on progression to ESRD, however, the presence of comorbidities might have the possibility to reduce the effect of depression on the renal outcome in patients with advanced diabetic nephropathy.