Cerebrovascular Disease in Maintenance Hemodialysis Patients: Results of the HEMO Study

Abstract

Cerebrovascular disease (CBVD) in hemodialysis patients is associated with significant morbidity and mortality. A secondary analysis of CBVD in the Hemodialysis (HEMO) Study was performed. Specific objectives were to: (1) determine risk factors for the presence of CBVD at baseline, (2) assess risk factors for the subsequent occurrence of cerebrovascular deaths, and (3) analyze the effects of dose and flux on cerebrovascular mortality. The HEMO Study was a randomized multicenter study evaluating the effects of high-dose versus standard-dose and high-flux versus low-flux hemodialysis. There were 1,846 patients enrolled, with a mean follow-up of 2.84 years. Factors associated with the baseline presence of CBVD included age (P < 0.0001), presence of any cardiac disease (P < 0.0001), and diabetes mellitus (P < 0.0001). There were 65 deaths caused by CBVD (event rate, 1.2/100 patient-years). Multivariate Cox regression using a backward-variables selection procedure showed that diabetes, lower albumin level, greater hematocrit, and lower body mass index at baseline were associated significantly with subsequent CBVD death. There was no effect of flux or dose on overall rate of CBVD deaths. However, an interaction was found between baseline CBVD status and flux intervention on CBVD death (P = 0.016). In the subgroup of patients without the baseline presence of CBVD, high-flux dialysis was associated with a lower risk for death caused by CBVD (P = 0.016). A borderline interaction between years of dialysis therapy and flux on subsequent CBVD death was detected (P = 0.05). The beneficial effect of high flux was evident in those on hemodialysis therapy for longer than 3.7 years (P = 0.012). High flux was associated with decreased CBVD mortality in those without known CBVD at baseline and those on hemodialysis therapy for longer than 3.7 years. This secondary analysis strengthens, but does not prove, the hypothesis that high-flux treatment may attenuate the death rate from vascular disease.