Vitamin D deficiency is associated with mortality and adverse vascular access outcomes in patients with end-stage renal disease

Abstract

Plasma 25 hydroxycholecalciferol (vitamin D) deficiency has been associated with adverse cardiovascular outcomes in epidemiologic studies. Chronic kidney disease is associated with loss of 1α-hydroxylase and consequently vitamin D deficiency. We hypothesized that vitamin D deficiency was associated with increased mortality and increased vascular access failure in patients undergoing permanent vascular access for end-stage renal disease. This retrospective cohort study analyzed 128 patients undergoing permanent vascular access surgery between 2003 and 2012 for whom concurrent plasma vitamin D levels were also available. Levels were considered deficient at<20ng/mL. Multivariable analysis was used to determine the association between vitamin D and mortality and vascular access outcomes. The mean age was 66.7years, 96.8% were male, 32.0% were African American, and 60.9% had diabetes mellitus. In the entire cohort, 55.5% were vitamin D-deficient, despite similar rates of repletion among the vitamin D-deficient and nondeficient groups. During a median follow-up of 2.73years, there were 40 deaths (31%). Vitamin D-deficient patients tended to be younger (P= .01) and to have higher total cholesterol (P= .001) and lower albumin (P= .017) and calcium (P= .007) levels. Despite their younger age, mortality was significantly higher (P= .026) and vascular access failure was increased (P= .008) in the vitamin D-deficient group. Multivariate logistic regression analysis found vitamin D deficiency (odds ratio [OR], 3.64; 95% confidence interval [CI], 1.12-11.79; P= .031), hemodialysis through a central catheter (OR, 3.08; 95% CI, 1.04-9.12; P= .042), coronary artery disease (OR, 3.08; 95% CI, 1.06-8.94; P= .039), increased age (OR, 1.09; 95% CI, 1.03-1.15; P= .001), and albumin (OR, 0.27; 95% CI, 0.09-0.83; P= .023) remained independent predictors of mortality. Vitamin D deficiency (hazard ratio [HR], 2.34; 95% CI, 1.17-4.71; P= .02), a synthetic graft (HR, 3.50; 95% CI, 1.38-8.89; P= .009), and hyperlipidemia (HR, 0.42; 95% CI, 0.22-0.81; P= .01) were independent predictors of vascular access failure in a Cox proportional hazard model. Vitamin D deficiency is highly prevalent in patients undergoing vascular access procedures. Patients who are deficient in vitamin D have worse survival and worse vascular access outcomes. Further study is warranted to assess whether aggressive vitamin D repletion will improve outcomes in this population.