Effects of cholecalciferol supplementation in patients with low vitamin D levels and chronic heart failure - a randomized double blind controlled trial

Abstract

Purpose: To investigate the effects of cholecalciferol administration to CHF patients with low vitamin D (VD) levels on physical performance, echocardiographic and hormonal parameters. Methods: From March to December 2012, in a randomized, double blind, placebocontrolled trial, 33 patients (age 78+/-7 - M 15) with stable CHF, VD =30ml/min (latitude 45N), received 300000 U of oral cholecalciferol plus 50000 U/month for six months(17) or placebo(16). The primary end point was distance at 6 minute walking test (6MWT) at three and six months, secondary end points were hormonal (PTH, Renin, BNP, FGF23) and echocardiographic (chamber size, systolic/diastolic function) changes. Results: After six months VD levels significantly rose in both groups even if treated group reached higher levels (38.2+/-7.0 vs 14.3+/-7.2). In treated group PTH drop significantly at third month but not at sixth (76.8+/-50.5 t0; 50.2+/-20.3 3mo; 68.1+/-45.2 6mo), and 6MWT improved at three months (from 210+/-104 mt to 225+/-94 mt p.033) but not at six. Echocardiographic and hormonal parameters were unchanged in both groups. Among treated patients improvement of 6MWT was positively related to baseline PTH (p.027) and negatively to GFR (p.030); this was not seen in placebo group. Conclusion: In CHF our scheme of VD supplementation produced transient improvement of 6MWT and PTH but not of echocardiographic and hormonal parameters. Due to relation of 6MWTand basal PTH in treated patients, it might be possible that a more restrictive patient selection (hyperPTH) and higher VD doses, driven by PTH levels, would produce better and longer results.