Effect of vitamin-D analogue on albuminuria in patients with non-dialysed chronic kidney disease stage 4–5: a retrospective single center study

BACKGROUND: The vitamin D receptor activator paricalcitol has been shown to reduce albuminuria. Whether this is a unique property of paricalcitol, or common to all vitamin D analogues, is unknown. The primary aim of this study was to evaluate the effect of alfacalcidol on proteinuria, measured as 24 hour (24 h) albuminuria, in patients with chronic kidney disease (CKD) stage 4–5 being treated for secondary hyperparathyroidism (sHPT). METHODS: A retrospective single-center study including adult patients with CKD 4–5, undergoing treatment for sHPT with alfacalcidol, with macroalbuminuria in minimum one 24 h urine collection. Patients were identified in a prospectively collected database of all patients with S-creatinine > 300 μM or creatinine clearance < 30 ml/min. The observation period was from 1(st) of January 2005 to 31(st) of December 2009. Phosphate binders and alfacalcidol were provided to patients free of charge. RESULTS: A total of 146 macroalbuminuric patients were identified, and of these, 59 started alfacalcidol treatment during the observation period. A 12% reduction in 24 h albuminuria was seen after starting treatment. In 19 patients with no change in renin-angiotensin-aldosteron-system (RAAS) inhibition, the reduction in albuminuria was 16%. The reduction remained stable over time (9%) in a subgroup of patients (n = 20) with several urine collections before and after the start of alfacalcidol-treatment. CONCLUSION: The present study supports experimental and clinical data on antiproteinuric actions of activated vitamin D analogues, and suggests that this may be a class-effect.