Statins and vitamin D: a friendly association in pre-dialysis patients

The increased mortality rate observed in patients with chronic kidney disease is related to the high prevalence of cardiovascular disease in this population. Recently, it has been shown that interventional therapy with statins and/or vitamin D could improve the outcomes of these patients. The aim of this study was to identify the risk factors for mortality in a group of patients with chronic kidney disease (stages 4 and 5--pre-dialysis) and verify whether vitamin D and statins could change the outcome. We included 95 patients (mean age--69.4) with stages 4 and 5 (pre-dialysis) of our "low-clearance" outpatient clinic, with an average eGFR of 16.9 ml/min and a mean follow-up of 24.1 months. Several biological, nutritional, laboratory and inflammatory parameters were analysed at baseline. Our population was divided into three groups: G-I, patients not medicated with either vitamin D or statins; G-II, patients medicated with either vitamin D or statins; and G-III, patients medicated with vitamin D and statins. We found (ANOVA) that the serum levels of pre-albumin (P = 0.018) and PTH (P = 0.03) were lower in G-I. Concerning the inflammatory parameters, G-I showed higher levels of hsCRP (P = 0.014) and a trend to higher IL-6 levels (P = 0.077). We found the actuarial survival at 30 months (Kaplan-Meier), to be 56.4% in G-I, 82.3% in G-II and 100% in G-III (log rank = 13.08 P = 0.0014). Using the Cox proportional hazards model, we found that the existence of coronary artery disease (P = 0.0001) and the absence of medication with vitamin D and/or statins (P = 0.005) independently influenced the mortality of our patients. In conclusion, we found, in our study, that patients under vitamin D and statins (with a synergistic effect) were less inflamed and showed a lower mortality rate.