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 1st of January 2005 to 31st 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.