Insomnia in patients on incident maintenance dialysis and the risk of major acute cardio-cerebrovascular events and all-cause mortality

Abstract

Background. Insomnia is a known risk factor for cardio-cerebrovascular disease in the general population; however, its effect on cardio-cerebrovascular outcomes in end-stage kidney disease patients is unclear. Therefore, this study aimed to investigate the asso- ciation between cardio-cerebrovascular outcomes and insomnia in patients who initiated maintenance dialysis. Methods. This study used nationwide Korean health insurance claims data to analyze 79 420 patients who initiated maintenance dialysis from January 2009 to December 2017. Insomnia was defined using claim codes and sleep medication prescription data. Patients were categorized according to the presence of insomnia before and after dialysis initiation: (i) no insomnia, (ii) insomnia before dialysis only (improved insomnia), (iii) insomnia after dialysis only (developed insomnia) and (iv) insomnia in both periods (persistent insomnia). The primary and secondary outcomes were major adverse cardiac and cerebrovascular events (MACCE) and all-cause mortality, respectively. The outcome risks were estimated by Cox regression models with inverse probability of treatment weighting. Results. The mean age was 61.4 ±13.4 years, and 39.7% were women. During the transition period from pre-dialysis to maintenance dialysis, 13.2% experienced insomnia. The insomnia groups showed significantly higher risks for MACCE [weighted hazard ratios (95% confidence intervals): developed insomnia, 1.26 (1.25–1.28); improved insomnia, 1.31 (1.29–1.33); persistent insomnia, 1.39 (1.37–1.41)] and higher all-cause mortality risks than the no insomnia group. The insomnia-related cardio-cerebrovascular disease risk elevation was more prominent in younger and male patients. Conclusions. Insomnia may increase cardio-cerebrovascular disease and all-cause mortality risk among end-stage kidney disease patients who initiate maintenance dialysis.