Exploring the Prevalence of Functional Cognitive Impairment in People on Maintenance Hemodialysis Therapy

Research Objectives: To determine the proportion of people on chronic hemodialysis who demonstrate functional cognitive impairment on a standardized, performance-based assessment, while also comparing its results to a routinely administered cognitive screening tool and self-report functional disability measures.

Design: Multi-centre, descriptive, cross-sectional study.

Setting: Two in-hospital dialysis units and two self-care dialysis units in Toronto, Canada serving community-dwelling adults undergoing hemodialysis.

Participants: People on hemodialysis treatment for kidney failure were randomly selected to participate from the study sites if they met the study eligibility criteria (over 18 years of age, on dialysis for >3 months, medically stable, no significant visual impairment or dementia diagnosis, able to provide informed consent in English). We recruited 103 participants of 353 screened, which met our recruitment expectation and enabled estimation of the population prevalence of daily living dysfunction within a 95% confidence margin of ±10%.

Interventions: Not applicable.

Main Outcome Measures: The UPSA-B is a standardized, performance-based functional cognitive assessment that requires participants to complete a series of simulated daily living tasks relevant to finances and communication. The MoCA, Barthel Index, and Lawton-Brody IADL scales are validated paper-based assessments commonly administered to assess cognitive and functional status in various healthcare settings and different patient populations, including kidney failure. We assessed the proportion of participants who exhibited impairment while completing routine cognitive tasks on the UPSA-B (≤ 60), and the proportion who scored as cognitively impaired ( < 26) on the MoCA. We also calculated the correlations between the UPSA-B and the MoCA, the Barthel Index, and Lawton-Brody IADL Scales.

Results: The mean age was 68 years old, 29 participants (28%) were female, and the median dialysis vintage was 36 months. 27 (26%) participants displayed functional cognitive impairment on the UPSA-B (95% CI: 18-36%), while 90 (87%) participants scored as cognitively impaired on the MoCA (95% CI: 79-93%). There was a strong correlation between the UPSA-B and the MoCA (r = 0.685, p < 0.001); a weak correlation between the UPSA-B and the Barthel Index (r = 0.279, p < 0.001); and a moderate correlation between the UPSA-B and Lawton-Brody IADL Scale (r = 0.378, p < 0.001).

Conclusions: Our findings support that cognitive impairment is common in people on chronic hemodialysis, and suggest it interferes with the ability to complete routine daily tasks in approximately 1/4 of patients. Future research should explore cognitive rehabilitation interventions to minimize the impact of cognitive impairment on everyday life in people on maintenance hemodialysis.

Author(s) Disclosures: No conflicts of interest to disclose.