Cognitive function and 3-year mortality in the very elderly Chinese population with chronic kidney disease

Kunhao Bai,1,2 Yujing Pan,3 Fanghong Lu,4 Yingxin Zhao,4 Fang Wang,1,5 Luxia Zhang1,5,6 1Renal Division, Department of Medicine, Peking University First Hospital, Beijing, People’s Republic of China; 2Department of Endoscopy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong, People’s Republic of China; 3Renal Division, Department of Medicine, Peking University International Hospital, Beijing, People’s Republic of China; 4Cardio-Cerebrovascular Control and Research Center, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, People’s Republic of China; 5Peking University Institute of Nephrology, Peking University Health Science Center, Beijing, People’s Republic of China; 6Center for Data Science in Health and Medicine, Peking University, Beijing, People’s Republic of China Background: Cognitive function has been suggested to be correlated with mortality, while studies regarding the association among the very elderly population with chronic kidney disease (CKD) are extremely limited.Aim: To explore the association between cognitive function and mortality among the very elderly Chinese population with CKD.Methods: This prospective study included 163 Chinese participants aged 80 years or older with CKD. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. Cognitive function was evaluated using the mini-mental state examination (MMSE) at baseline. Participants were divided into three groups based on the MMSE score. Cox proportional hazard models were used to assess the contribution of cognitive function to mortality.Results: During a median follow-up of 28 months, 24 (14.7%) participants died, and 14 of the events were cardiovascular death. After making adjustment for potential confounders, every 1-point increase of MMSE score was associated with 29% decreased risk of all-cause mortality (adjusted hazards ratio [HR], 0.71; 95% CI, 0.58–0.87) and 39% decreased risk of cardiovascular mortality (adjusted HR, 0.61; 95% CI, 0.44–0.83). Compared with participants with top category of MMSE score, the adjusted HRs for all-cause mortality and cardiovascular mortality among those with bottom category of MMSE score were 8.18 (95% CI, 2.05–32.54) and 14.72 (95% CI, 1.65–131.16).Conclusion: Cognitive function was associated with all-cause mortality and cardiovascular mortality among the very elderly population with CKD. Keywords: cognitive function, mortality, chronic kidney disease, very elderl