We hypothesized that adding 5 days of prednisone to standard therapy for acute pulmonary exacerbations in patients with cystic fibrosis (CF) would result in a more rapid and greater increase in lung function.

CF patients with an acute pulmonary exacerbation were randomized to receive oral placebo or prednisone, 2 mg/kg/d up to 60 mg, on days 1 to 5 in addition to standard therapy. Study evaluations on days 1 to 6, 14, and 42 included spirometry, glucose measurements, sputum analysis, and symptom scores.

Twelve subjects were randomized to each arm. The slope of FEV(1) between day 1 and day 6 did not differ between evaluable subjects in the prednisone vs placebo groups (52 mL/d vs 51 mL/d, respectively). Mean increase in FEV(1) percentage of predicted did not differ significantly between prednisone vs placebo groups (day 6 [mean +/- SD], 12.2 +/- 5.2% vs 8.1 +/- 10.5%; day 14, 14.7 +/- 8.8% vs 10.2 +/- 11.2%, respectively). Sputum inflammatory markers and symptom scores decreased between day 1 and day 14, but mean values did not differ between groups. Glucosuria occurred in six prednisone subjects, two of whom had hyperglycemia develop.

In this pilot study, addition of oral corticosteroids to standard CF pulmonary exacerbation therapy did not result in a statistically significant effect on lung function or sputum markers of inflammation. Based on a trend toward improvement in pulmonary function with prednisone therapy, we obtained information for power calculations for a definitive study: 250 randomized subjects are required to detect a four-percentage-point treatment effect in FEV(1) percentage of predicted at day 14 to discriminate between null and alternative hypotheses.