Time to spirometric and exercise response in 4-week oral corticosteroid trial for stable COPD patients.

Objective: Little evidence supports the commonly recommended 2-week duration for an oral corticosteroid trial in stable COPD patients. We aimed to assess the time to spirometric and exercise responses in stable COPD patients undergoing an oral corticosteroid trial.
Methods: In a pilot study a 28-day trial with prednisone 0.5 mg/kg bodyweight was performed in all outpatients meeting entry criteria during one calendar year. Response was assessed by spirometry (twice weekly) and 6-minute walk distance (6MWD, weekly). Of 36 moderate to severe COPD patients started on prednisone, 30 completed the study according to the protocol.
Results: The mean post-bronchodilator forced expiratory volume in 1 second (FEV1) was 49.5% predicted and the 6MWD was 444 m at baseline. On the basis of spirometry (post-bronchodilator FEV1 > or = 15% and > or = 200 ml) 12 patients were responders. Five additional patients improved their 6MWD by > or = 55 m (exercise responders). Of all 17 responders six (35%) responded between day 17 and 28 (4 spirometric and 2 exercise responders). Responders and non-responders showed a maximum FEV1 increase from baseline on day 24 of 264 ml and 70 ml, respectively.
Conclusion: An oral corticosteroid trial of only 2 weeks' duration may miss a clinically significant number of corticosteroid-responsive stable COPD patients.