Vitamin D Status and All-Cause Mortality in Patients With Chronic Kidney Disease: A Systematic Review and Dose-Response Meta-Analysis Publisher Pubmed



Jayedi A¹ ; Soltani S² ; Shabbidar S¹ Show Affiliations
Source: Journal of Clinical Endocrinology and Metabolism Published:2017

Abstract

Context: The prevalence of Vitamin D deficiency is high in patients with chronic kidney disease (CKD). Less attention has been paid to measurement and correction of a serum level of 25-hydroxyVitamin D [25(OH)D] in these patients. Objective: We examined the association between different levels of serum 25(OH)D and risk of allcause mortality in patients with CKD. Data Sources: Systematic search was done using MEDLINE and EMBASE from inception to November 2016. Reference lists of all relevant articles and reviews also were searched. Study Selection: Prospective or retrospective cohort studies that reported risk estimates of all-cause mortality for three or more categories of serum 25(OH)D in patients with CKD were selected. Studies that reported results as continuous also were included. Two independent investigators screened and selected the articles. Of 1281 identified studies, 13 prospective cohort studies, two retrospective cohort studies, and one nested case-control study with 17,053 patients and 7517 incident deaths were included. Data Extraction: Two independent authors extracted data from included studies. Any discrepancies were resolved through consensus. Data Synthesis: Reported risk estimates were combined using a random-effects model. Summary risk estimates of all-cause mortality were 1.63 [95% confidence interval (CI), 1.32 to 1.94] for severe deficiency (,10 ng/mL), 1.22 (95% CI, 1.09 to 1.35) for mild deficiency (10 to 20 ng/mL), and 1.12 (95% CI, 1.06 to 1.18) for insufficiency (20 to 30 ng/mL). Results were more evident in dialysisdependent patients. A 10-ng/mL increment in serum 25(OH)D was associated with a 21% reduction in the risk of overall mortality (relative risk, 0.79; 95% CI, 0.70 to 0.87). Lower risk of all-cause mortality was observed at a serum 25(OH)D of ;25 to 30 ng/mL. Dialysis treatment was one of the sources of variation between studies. Conclusions: Higher levels of serum 25(OH)D were associated with a lower risk of all-cause mortality in patients with CKD, but we have no conclusive evidence regarding serum levels of .35 ng/mL. Copyright © 2017 Endocrine Society.