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Vitamin D treatment in kidney disease cuts deaths by one-fourth

An article published online in advance of the August, 2008 issue of the Journal of the American Society of Nephrology reported that giving an oral form of activated vitamin D known as calcitriol to chronic kidney disease patients was associated with a 25 percent reduction in mortality over a 1.9 year period. Calcitriol has been previously associated with improved survival when given intravenously to kidney dialysis patients to treat hyperparathyroidism; however, its effect in nondialysis kidney disease patients was unknown.

In a study funded by the National Institutes of Health, Dr. Bryan Kestenbaum of the University of Washington’s Harborview Medical Center in Seattle and his colleagues at the Puget Sound Veterans Affairs Medical Center evaluated 1,418 nonhypercalcemic patients with stage 3 to 4 (moderate to severe) chronic kidney disease. Some of the patients were being treated with oral calcitriol to help reduce elevated parathyroid hormone levels, a condition that was present in all participants. Over the 1.9 year follow-up period, 408 deaths occurred.

When mortality rates for the two groups were compared, deaths were 26 percent lower among those who received vitamin D, following adjustment for differences in age, parathyroid hormone levels, and other factors. Subjects who received calcitriol also had a lower risk of developing end stage kidney disease or requiring dialysis. The combined risk of death or dialysis was 20 percent lower among patients treated with calcitriol, a finding that was not related to calcitriol’s effect on parathyroid hormone.

“Although activated vitamin D is known to influence many biological processes, previous clinical knowledge is limited to its effect on parathyroid hormone levels,” Dr. Kestenbaum explained. “Recently, there has been an increased focus on the effects of vitamin D beyond those on bone health. Vitamin D deficiency has been associated with risk factors for cardiovascular disease, such as high blood pressure, diabetes, and inflammation.”

“Randomized clinical trials are needed to test the hypothesis that vitamin D therapy can improve cardiovascular health and survival in CKD,” he added. “Future studies should also examine the role of nonactivated vitamin D, which is less expensive and less toxic.”