The effects of dialysis modality choice on cognitive functions in patients with end-stage renal failure: a systematic review and meta-analysis

Introduction: Cognitive dysfunction is a major consequence of end-stage renal disease (ESRD) and has further detrimental effects on both functionality and the quality of life for patients. While peritoneal dialysis is generally advocated in ESRD, there is a substantial knowledge gap about the differential effects of chronic dialysis modalities on cognitive dysfunction and decline. The aim of this meta-analysis is to evaluate cognitive function in peritoneal dialysis versus hemodialysis patients. Methods: We performed a systematic review in different databases to identify studies that assessed the effect of different dialysis modalities on cognitive functions. Inclusion criteria for our meta-analysis were all studies that compared the effects of peritoneal dialysis on cognitive functions compared to intermittent hemodialysis. The data collected were the name of the first author, journal title, year of publication, country where the study was conducted, number of patients in the peritoneal dialysis and hemodialysis arms and methods of assessment of cognitive functions. Results: Out of 2769 abstracts reviewed in different databases, 11 papers were included in our meta-analysis. Altogether, 195,774 patients were included in the final analysis. The forest plot analysis of the rate of cognitive impairment in different dialysis modalities showed decreased risk of cognitive impairment in the peritoneal dialysis population compared to hemodialysis patients (relative risk = 0.634, confidence interval ranges from 0.508 to 0.790). There was evidence of significant heterogeneity among studies with p < 0.0001 and I2 = 85.5%. The sensitivity analysis limited to studies on patients younger than 65 years of age showed similar results (relative risk = 0.516; 95% confidence intervals: 0.379–0.704). Conclusion: Patients on peritoneal dialysis demonstrated a lower odd of cognitive dysfunction compared to those on hemodialysis. Future prospective studies should assess cognitive decline as a meaningful outcome in dialysis patients.