Cognitive impairment and health outcomes in non-dialysis chronic kidney disease: a systematic review and meta-analysis

Background: Cognitive impairment is prevalent in individuals with chronic kidney disease (CKD), but its effects on health outcomes remain unclear. While cognitive impairment can affect self-management, its role in CKD has been insufficiently explored. This systematic review aimed to examine the association between cognitive impairment and health outcomes or self-management ability among persons with CKD. Methods: Searches were performed in June 2024 on Embase, MEDLINE, CINAHL, PsycINFO, Web of Science, PubMed and grey literature databases for longitudinal or cross-sectional studies examining associations between cognitive impairment (using any validated measure) and health outcomes or ability to self-manage in adults with CKD not on kidney replacement therapy. Health outcomes included mortality, kidney disease progression, hospitalization and healthcare utilization, cardiovascular and cerebrovascular events, and health-related quality of life (HRQoL). Risk of bias was assessed using the ROBINS-E ('Risk of bias in non-randomized studies of exposure') tool. Results: Fourteen studies were included. Cognitive impairment was associated with increased all-cause and cardiovascular mortality, higher risk of cardiac arrhythmia, stroke and transient ischaemic attack, lower HRQoL, and higher healthcare utilization. Mixed results were seen in studies examining the association between cognitive impairment and kidney disease progression. No studies with self-management measures as an outcome were identified. Conclusions: Cognitive impairment is associated with poor health outcomes in persons with CKD, although evidence was limited for some outcomes. No causal link could be established due to potential residual confounding by frailty or shared comorbidities. Further research is required to explore potential causal pathways and the role of cognitive impairment in CKD self-management.