Risk factors for cognitive impairment in patients undergoing hemodialysis: an umbrella review and meta-analysis

Cognitive impairment is a common complication in patients undergoing maintenance hemodialysis. This umbrella review and meta-analysis systematically evaluated the factors associated with cognitive impairment and, separately, cognitive frailty in adults receiving hemodialysis. PubMed, Web of Science, Embase, and the Cochrane Library were searched from inception to January 2026. Five meta-analyses involving 97 associations were included; three evaluated cognitive impairment and two evaluated cognitive frailty. For cognitive impairment, older age, female sex, diabetes, cerebrovascular disease, multiple comorbidities, impaired physical performance, lower hemoglobin levels, and inflammatory markers were associated with increased risk, whereas higher educational attainment was associated with reduced risk (OR = 0.21, 95% CI: 0.13-0.34). For cognitive frailty, older age, female sex, depression (OR = 4.66, 95% CI: 2.98-7.27), stroke history (OR = 2.94, 95% CI: 1.72-5.03), comorbidities, malnutrition, longer dialysis duration (OR = 2.30, 95% CI: 1.49-3.53), low-flux hemodialysis (OR = 4.16, 95% CI: 1.97-8.79), and interdialytic hypotension (OR = 2.42, 95% CI: 1.53-4.21) were associated with increased risk, whereas higher education and serum albumin were protective. Only two associations had moderate-certainty evidence; all others were rated low or very low. Cognitive impairment and cognitive frailty are associated with multiple demographic, clinical, and dialysis-related factors but represent distinct outcomes that should be interpreted separately. Further high-quality prospective studies are warranted.