Risk of dementia in peritoneal dialysis patients compared with hemodialysis patients.

BACKGROUND: Compared with similarly aged controls, patients with end-stage renal disease (ESRD) have a higher prevalence of cognitive impairment and more rapid cognitive decline, which is not explained by traditional risk factors alone. Since previous small studies suggest an association of cognitive impairment with dialysis modality, we compared incident dementia among patients initiating hemodialysis (HD) vs peritoneal dialysis (PD) in a large national cohort.

METHODS: This is a retrospective cohort study of incident dialysis patients in the United States from 2006 to 2008 with no diagnosis of dementia prior to beginning dialysis. We evaluated the effect of initial dialysis modality on incidence of dementia, diagnosed by Medicare claims data, adjusted for baseline demographic and clinical data from the USRDS registry.

RESULTS: Our analysis included 121,623 patients, of whom 8,663 initiated dialysis on PD. The mean age of our cohort was 69.2 years. Patients who initiated PD had a lower cumulative incidence of dementia than those who initiated HD (1.0% vs 2.7%, 2.5% vs 5.3%, and 3.9% vs 7.3% at 1, 2, and 3 years, respectively). The risk of dementia for patients who started on PD was lower compared with those who started on HD, with a hazard ratio (HR) = 0.46 [0.41, 0.53], in an unadjusted model and HR 0.74 [0.64, 0.86] in a matched model.

CONCLUSIONS: Dialysis modality is associated with incident dementia in a cohort of older ESRD patients. This finding warrants further investigation of the effect of dialysis modality on cognitive function and evaluation for possible mechanisms.