Cognitive impairment in peritoneal dialysis patients

Background: The prevalence of moderate to severe cognitive impairment in hemodialysis patients is more than double the prevalence in the general population. This study describes cognitive impairment occurrence in a peritoneal dialysis cohort compared with a cohort without chronic kidney disease (CKD).

Study design: Cross-sectional study.

Setting & participants: 51 English-speaking peritoneal dialysis patients from 2 urban dialysis units compared with 338 hemodialysis patients from 16 urban dialysis units and 101 voluntary controls without CKD from urban general medicine clinics.

Predictor: 45-minute battery of 9 validated neuropsychological tests (cognitive domains memory, executive function, and language).

Outcomes: Mild, moderate, or severe cognitive impairment, classified according to a previously designed algorithm.

Results: Of the peritoneal dialysis cohort, 33.3% had no or mild, 35.3% had moderate, and 31.4% had severe cognitive impairment; corresponding values were 60.4%, 26.7%, and 12.9% of the non-CKD cohort and 26.6%, 36.4%, and 37.0% of the hemodialysis cohort. A logistic regression model including age, sex, race, education, hemoglobin level, diabetes, and stroke showed that only nonwhite race (P = 0.002) and low education (P = 0.002) were associated with moderate to severe cognitive impairment in the peritoneal dialysis cohort. Compared with hemodialysis patients, more peritoneal dialysis patients had moderate to severe memory impairment (58% vs 51%), but fewer had impaired executive function (one-third vs one-half). Peritoneal dialysis was associated with a more than 2.5-fold increased risk of moderate to severe global cognitive impairment compared with no CKD (OR, 2.58; 95% CI, 1.02-6.53), as was hemodialysis (OR, 3.16; 95% CI, 1.91-5.24), in an adjusted logistic regression model.

Limitations: Small sample size, participation rate somewhat low.

Conclusions: Similar to hemodialysis patients, two-thirds of peritoneal dialysis patients had moderate to severe cognitive impairment, enough to interfere with safely self-administering dialysis and adhering to complex medication regimens. These patients could benefit from cognitive assessment before and periodically after dialysis therapy initiation.