Risk of intracranial hemorrhage associated with autosomal dominant polycystic kidney disease in patients with end stage renal disease

BACKGROUND: An analysis of intracranial hemorrhage (ICH) in a national sample of autosomal dominant polycystic kidney disease (ADPKD) patients receiving long-term dialysis has not been reported. It is often assumed that patients with ADPKD are not at increased risk of ICH after starting dialysis. We hypothesized that patients with ADPKD would have a higher subsequent risk of ICH even after the start of chronic dialysis. METHODS: Retrospective cohort study of Medicare primary patients with and without ADPKD in the United States Renal Data System (USRDS), initiated on chronic dialysis or transplanted between 1 January 1999 and 3 July 2009, and followed until 31 December 2009. Covariates included age, gender, race, prior stroke, diabetes mellitus, dialysis modality, body mass index, serum albumin and other co-morbid conditions from the Medical Evidence Form. Primary outcome was ICH, based on inpatient and outpatient Medicare claims, and all-cause mortality. Kaplan-Meier analysis was used for unadjusted assessment of time to events. Cox regression was used for assessment of factors associated with ICH and mortality. We performed competing risk regression using kidney transplant and death as competing risks. Kidney transplant was also modeled as a time-dependent covariate in Cox regression. RESULTS: Competing risk regression demonstrated that ADPKD had a subhazard ratio 2.97 for ICH (95% CI 2.27-3.89). Adjusted Cox analysis showed that ADPKD patients had an AHR for death of 0.59 vs. non-ADPKD patients (95% CI 0.57-0.61). CONCLUSIONS: ADPKD is a significant risk factor for ICH among patients on maintenance dialysis. Our Medicare primary cohort was older than in previous studies of intracranial aneurysm rupture among ADPKD patients. There are also limitations inherent to using the USRDS database.