Patients with end-stage renal disease (ESRD) who initiate renal replacement therapy on peritoneal dialysis (PD) are at lower risk of dementia than those who start on hemodialysis (HD), researchers concluded.
In a retrospective study of 121,623 patients initiating dialysis, Dawn F. Wolfgram, MD, of the Medical College of Wisconsin in Milwaukee, and colleagues found that those who started on PD had a 25% decreased risk of dementia compared with those who started on HD, after adjusting for age, gender, and other potential confounders. They obtained similar results when patients were matched by propensity score.
“This is the largest study to date in support of the hypothesis that the HD process itself, rather than simply the presence of ESRD, may contribute to the well-known higher prevalence of dementia among persons with ESRD,” the authors wrote in Peritoneal Dialysis International.
Dr. Wolfgram’s team noted that their study “emphasizes the need for clinicians to regularly assess cognitive function among persons undergoing dialysis.” By helping clinicians tailor management to patients’ cognitive abilities, early recognition of dementia may improve patient outcomes, they stated.
PD was the initial dialysis modality for 8,663 of the 121,623 study subjects. The mean age of the total cohort was 69.2 years.
The researchers used U.S. Renal Data System data for incident ESRD patients during calendar years 2006–2008. For all patients, they obtained Medicare claims data for 2004 through 2009, which includes ICD-9 comorbid disease diagnosis codes.
“Our use of Medicare data allowed us to exclude people who carried a dementia diagnosis at baseline, or who were recognized as having dementia during the 90 days after they initiated dialysis,” they wrote. “Thus we were not simply documenting that persons with dementia are unlikely to be able to initiate PD, a therapy which requires greater involvement of patients in care.”
The investigators also acknowledged study limitations. For example, they pointed out that non-medical factors impact the choice between PD and HD. “Physicians are more likely to encourage patients with subtle evidence of cognitive impairment to choose HD as their initial modality, biasing our results toward higher dementia risk in those initiated on HD. Although we excluded patients with pre-existing dementia from our analysis, it is possible that significant differences in baseline cognitive function between the PD and HD groups affected our results.”
Another limitation was that the researchers required 2 years of Medicare eligibility prior to the diagnosis of ESRD. As a result, their cohort was substantially older than the overall ESRD population and may have been healthier due to a survival effect, they noted. “Thus we cannot extrapolate our findings to younger persons with ESRD.”