Cognitive Impairment and Progression of CKD

Background Cognitive impairment is common among patients with chronic kidney disease (CKD); however, its prognostic significance is unclear. We assessed the independent association between cognitive impairment and CKD progression in adults with mild to moderate CKD. Study Design Prospective cohort. Setting & Participants Adults with CKD participating in the CRIC (Chronic Renal Insufficiency Cohort) Study. Mean age of the sample was 57.7±11.0 years and mean estimated glomerular filtration rate (eGFR) was 45.0±16.9mL/min/1.73m 2 . Predictor Cognitive function was assessed with the Modified Mini-Mental State Examination at study entry. A subset of participants 55 years and older underwent 5 additional cognitive tests assessing different domains. Cognitive impairment was defined as a score > 1 SD below the mean score on each test. Covariates included demographics, kidney function, comorbid conditions, and medications. Outcomes Incident end-stage renal disease (ESRD) and incident ESRD or 50% decline in baseline eGFR. Results In 3,883 CRIC participants, 524 (13.5%) had cognitive impairment at baseline. During a median 6.1 years of follow-up, 813 developed ESRD and 1,062 developed ESRD or a ≥50% reduction in eGFR. There was no significant association between cognitive impairment and risk for ESRD (HR, 1.07; 95% CI, 0.87-1.30) or the composite of ESRD or 50% reduction in eGFR (HR, 1.06; 95% CI, 0.89-1.27). Similarly, there was no association between cognitive impairment and the joint outcome of death, ESRD, or 50% reduction in eGFR (HR, 1.06; 95% CI, 0.91-1.23). Among CRIC participants who underwent additional cognitive testing, we found no consistent association between impairment in specific cognitive domains and risk for CKD progression in adjusted analyses. Limitations Unmeasured potential confounders, single measure of cognition for younger participants. Conclusions Among adults with CKD, cognitive impairment is not associated with excess risk for CKD progression after accounting for traditional risk factors.