In the paper by Cosio and colleagues on the effect of low-dose theophylline on the anti-inflammatory effects of steroids during exacerbations of chronic obstructive pulmonary disease (COPD), the authors concluded that recovery of forced expiratory volume in 1 s 3 months after the exacerbation and low mortality (although not statistically significant) in the theophylline group, in combination with the molecular effects described, provided a strong rationale for investigating further the potential clinical relevance of this therapeutic strategy in large randomised double-blind placebo controlled trials.1

In such trials, if the time of hospital discharge is taken as the end point instead of taking 3 months after the exacerbation as in the study by Cosio et al, it would better reflect the physiological events of a COPD exacerbation. In addition to addressing the limitations expressed by the authors in the article, consideration of clinical parameters such as symptoms, blood gases and the need for non-invasive ventilation in the outcome measures might add more strength to the evidence. Another factor which also needs to be considered is whether patients with COPD are on a pulmonary rehabilitation programme.