Commentary

In recent years, numerous clinical trials have been done to study the effects of pulmonary rehabilitation. The findings of Griffiths et al are consistent with those from previous studies. For example, a recent study by Guell et al found long term benefits with outpatient rehabilitation.¹ A salient contrast between these 2 studies was that Guell et al's programme did not emphasise patient education, whereas Griffiths and colleagues' programme devoted one third of the time to education. However, studies that tested the effects of educational interventions for pulmonary rehabilitation have not found benefits.^{2, 3}

Griffiths et al did a methodologically sound trial that provides additional support for pulmonary rehabilitation as an effective clinical intervention for chronic obstructive pulmonary disease. The programme was outpatient based, so the cost should be lower than that of inpatient programmes. The authors intend to follow up with an economic analysis of this trial, which will add further important information. Although long term benefits were found, the differences between control and intervention groups diminished over the 1 year interval. In view of this finding, studies that examine strategies for prolonging the benefits of pulmonary rehabilitation are warranted. Finally, because educational interventions have shown no measurable benefits, researchers should scrutinise the design of educational intervention studies. Inadequate instructional design could have caused the lack of effect of educational interventions.