The effect of vitamin D on COPD exacerbation: a double blind randomized placebo-controlled parallel clinical trial

To investigate the effect of supplementation of standard treatment (inhaled long-acting β2 agonists, anticholinergics and corticosteroids) with vitamin D on C reactive protein and pulmonary function tests in patients with COPD exacerbation.

Randomized, single-center, double-blind, placebo-controlled parallel trial. One teaching hospital Participants: 135 patients in pulmonary ward with moderate to severe COPD and exacerbations.120 patients fulfilled the study protocol.

Patients were randomly divided into three groups receiving 7 day treatment with 0.25 μg calcitriol daily (n = 45), 50000 IU daily of vitamin D (n = 45) or placebo (n = 45). An independent nurse was responsible for allocation, preparation, and accounting of trial medications.

Maximal expiratory flow volume (FEV1) and forced volume capacity curves (FVC) and Modified Medical Research Council (MMRC) scale.

Out of 135 patients who were recruited consecutively, 45 patients randomly were randomly assigned in three groups (balance blocked randomization.15 patients were dropped out due to non-compliance for second PFT. Intention to treat analysis was carried out for 120 participants. The difference between before and after treatment FEV1 and FEV1/FVC ratio had no significant difference between treatment groups and placebo. (P = 0.43, P = 0.51, respectively)but clinical improvement was significant in patients who received calcitriol. No side effects were reported.

Short term treatment with either calcitriol or 25(OH) 2Vit D didn't changed FEV1 or FVC in vitamin D sufficient patients with COPD exacerbation; nevertheless it can provide clinical benefit.

Iranian Registry of Clinical Trials no. IRCT138712271774N1. Registered 10 April 2011.