Activated vitamin D administered to patients with moderate to severe chronic kidney disease (CKD) reduces mortality by a fourth, according to the latest findings.

The findings are based on a study of 1,418 patients with moderate to severely impaired kidney function. They also had high parathyroid hormone levels (hyperparathyroidism), which can contribute to weakening of the bones in CKD patients.

Researchers identified a group that was being treated with calcitriol to lower parathyroid hormone levels, and another group that was not receiving calcitriol.

Patients with advanced CKD take calcitriol, an oral form of activated vitamin D, to treat elevated levels of parathyroid hormone, explained Bryan Kestenbaum of the University of Washington, one of the co-authors of the study.

During a two-year follow-up period, mortality rates were compared for patients who were and were not taking calcitriol. "We then adjusted for differences in age, kidney function, parathyroid hormone levels, other illnesses, and other medications," says Kestenbaum.

In the adjusted analysis, the overall risk of death was about 26 percent lower for patients taking calcitriol. Patients on calcitriol were also less likely to develop end-stage renal disease, requiring dialysis to replace lost kidney function.

"Recently, there has been an increased focus on the effects of vitamin D beyond those on bone health," Kestenbaum comments. "Vitamin D deficiency has been associated with risk factors for cardiovascular disease, such as high blood pressure, diabetes, and inflammation."

These findings will appear in the August issue of the Journal of the American Society of Nephrology.