Wolf M et al. (2008) Impact of activated vitamin D and race on survival among hemodialysis patients. J Am Soc Nephrol 19: 1379–1388

Black patients who start dialysis tend to have lower levels of vitamin D than non-Hispanic white patients, and are, therefore, presumably more likely to receive intravenous activated vitamin D. A recent study indicates that this difference in vitamin D treatment might contribute to the extended survival of black patients on dialysis compared with white patients.

Wolf et al. analyzed data from 9,303 patients (55% white, 35% black) in the US. At the initiation of dialysis, black patients had a higher mean parathyroid hormone level and a lower mean 1,25-dihydroxyvitamin D level than white patients (P <0.05 for both). More black patients than white patients received activated vitamin D (88% vs 71%; P <0.05), and baseline parathyroid hormone level was the strongest predictor of vitamin D treatment.

Black ethnicity was associated with a 32% (95% CI 23–39%) lower risk of death than white ethnicity, and use of activated vitamin D was associated with a 52% (95% CI 46–57%) decrease in the risk of death. Multivariate analysis revealed that black people who received vitamin D had a 16% lower risk of death than white people who received vitamin D (P <0.05); however, the survival advantage of black ethnicity disappeared when the dose of vitamin D was taken into account. By contrast, among vitamin D untreated individuals, black patients had a 35% higher risk of death than white ones (P <0.05).