Background: Besides its effect on calcium metabolism, vitamin D may play a part in preventing the onset and progression of cardiovascular disease (CVD) events. Only a few reports on the studies relating to whether vitamin D may reduce CVD events in patients with predialysis chronic kidney disease (CKD) are available, and many ambiguities remain.
Methods: We conducted a retrospective cohort study of 665 patients with predialysis CKD. With log-rank test using the Kaplan-Meyer survival curve, comparison of incidences of CVD events, CVD-related mortality, and all-cause mortality were made between patients in the alfacalcidol treatment group (107 patients) in the predialysis stage to whom alfacalcidol 0.25-0.5 microg/day was orally administered for at least 24 weeks, and patients in the nontreatment group (558 patients) who received no administration of alfacalcidol or other type of activated vitamin D and its analogues. Patients to whom alfacalcidol administration was discontinued within 24 weeks as well as initiation of dialysis of <24 weeks were excluded for this study. Factors relating to CVD events were examined using Cox's proportional hazards analysis.
Results: The mean follow-up period was 55.1 +/- 38.9 months in the alfacalcidol treatment group and 41.9 +/- 38.4 months in the nontreatment group. CVD events occurred in 172 patients during the follow-up period, and 74 of those occurred during the predialysis period. In the alfacalcidol treatment group, the incidence of cumulative CVD events was significantly lower. In relation to all-cause deaths and CVD-related deaths, the cumulative mortality rate was significantly lower in the alfacalcidol treatment group during the follow-up period. Throughout the follow-up period, the association between CVD events and alfacalcidol use was detected when adjusted for age, sex, diabetes, hypertension, use of renin-angiotensin system inhibitors, estimated glomerular filtration rate, and albumin and parathyroid hormone.
Conclusion: These data showed that oral administration of alfacalcidol for predialysis CKD patients was associated with reduced risk for CVD.