Self-Care Peritoneal Dialysis Patients with Cognitive Impairment Have a Higher Risk of Peritonitis in the Second Year

Introduction Cognitive impairment is common among patients on peritoneal dialysis (PD). We hypothesize that cognitive impairment has a negative impact on the outcome of patients on PD, especially with regard to peritonitis. Methods This was a single-center 2-year prospective cohort study involving 206 patients at 1 PD unit. Cognitive impairment was defined by the latest Hong Kong Montreal Cognitive Assessment Score (HK-MoCA) multiple cut-offs as determined by age and years of education. Eighty percent of patients had come back for interval HK-MoCA. The HK-MoCA was performed at baseline and after 1 year on PD. Potential risk factors for cognitive impairment and peritonitis were studied separately for the first and second year. Results For cognitive impairment at baseline, multivariate analyses showed that age (odds ratio [OR] 1.003, 95% confidence interval [CI] 1.003 – 1.065, p = 0.03), female sex (OR 3.57, 95% CI 1.60 – 7.97, p = 0.002), peripheral vascular disease (PVD) (OR 3.46, 95% CI 1.33 – 9.01, p = 0.01), and hemoglobin level (OR 0.60, 95% CI 0.43 – 0.84, p = 0.003) were statistically significant factors. For cognitive impairment at 1 year, multivariate analyses showed that age (OR 1.07, 95% CI 1.02 – 1.012, p = 0.007), female sex (OR 5.87, 95% CI 1.86 – 18.5, p = 0.003), and PVD (OR 3.68, 95% CI 1.07 – 12.84, p = 0.04) were statistically significant independent factors for cognitive impairment at 1 year. For self-care PD patients in the second year, patients with cognitive impairment had a higher rate of peritonitis and proportionately more patients suffered from both peritonitis and exit-site infection than non-cognitively impaired patients in the second year (0.50 vs 0.27 episodes per year, p = 0.048; 25% vs 7.2%, p = 0.049). Logistic regression showed that only HK-MoCA-defined cognitive impairment and HK-MoCA scores at 1 year were factors predicting peritonitis (risk ratio [RR] 3.2 [95% CI 1.03 – 9.95], p = 0.04 and RR 0.92 [95% CI 0.86 – 0.995], p = 0.04 respectively). Conclusions In summary, increasing age, female sex, anemia, and presence of PVD are risk factors for cognitive impairment in PD patients. Self-care PD with cognitive impairment at 1 year has a higher risk for PD-related peritonitis in the second year. Interval HK-MoCA assessment is recommended to detect cognitive impairment in our local PD patients.