Chronic Kidney Disease

Vitamin D Linked With Reduced Risk of Mortality in CKD Patients

Higher levels of 25-hydroxyvitamin D (25[OH]D) are associated with a reduced risk of all-cause mortality among patients with chronic kidney disease (CKD), according to a recent meta-analysis.

Patients with CKD often experience vitamin D deficiency. However, few studies have focused on measuring and correcting a serum level of 25(OH)D in this patient population.
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To assess the outcomes associated with different levels of 25(OH)D among patients with CKD, the researchers assessed 1281 identified studies, 13 prospective cohort studies, 2 retrospective cohort studies, and 1 nested case-control study with 17,053 patients and 7517 incident deaths.

Study data was obtained via MEDLINE and EMBASE databases from inception until November 2016. All data was collected by 2 independent authors. Studies that reported risk estimates of all-cause mortality for 3 or more categories of serum 25(OH)D among CKD patients were included in the analysis.

A random-effects model was used to combine reported risk estimates. Patients were assessed for severe 25(OH)D deficiency (less than 10 ng/mL), mild deficiency (10 to 20 ng/mL), and insufficiency (20 to 30 ng/mL).

Results indicated that the summary risk estimates of all-cause mortality were 1.63 among patients with severe deficiency, 1.22 among those with mild deficiency, and 1.12 among those with insufficiency. The researchers noted that these results were more evident in patients who had been dependent on dialysis.

Ultimately, the researchers found that 10-ng/mL increment in serum 25(OH)D was associated with a 21% lower risk of overall mortality. Furthermore, a lower risk of all-cause mortality was specifically observed at a serum 25(OH)D of approximately 25 to 30 ng/mL. Dialysis treatment was identified as a source of variation between studies.

“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 [higher than 35 ng/mL],” the researchers concluded.

—Christina Vogt

Reference:

Jayedi A, Soltani S, Shab-Bidar S. Vitamin D status and all-cause mortality in patients with chronic kidney disease: a systematic review and dose-response meta-analysis. J Clin Endocrinol Metab. 2017;102(7):2136-2145. doi:10.1210/jc.2017-00105.