This was a randomised multicentre trial comparing lung volume reduction surgery with continuing medical treatment in patients with severe emphysema (n=538 and 540, respectively, after exclusions). The primary outcomes were mortality and maximal exercise capacity 2 years after randomisation.

Overall mortality was similar in both groups (0.09 deaths per person-year for those undergoing surgery v 0.10 for those who did not). Exercise capacity after 24 months improved by more than 10 W in 16% of those undergoing surgery compared with 3% in the group receiving continuing medical treatment (p<0.001). In secondary analyses four subgroups were established, combining high or low exercise capacity with the presence or absence of predominantly upper lobe emphysema. In the patients with predominantly upper lobe emphysema and a low baseline exercise capacity, mortality was lower in the group who underwent surgery than in those who did not (death risk ratio 0.47, p=0.005); the converse was true in patients without predominantly upper lobe emphysema and a high exercise tolerance (risk ratio 2.06, p=0.02) and functional gain was negligible. There was no difference for the other subgroups.

Although this was a large, well conducted study with interesting results for physicians, the data should be interpreted with caution as mortality only differed in the secondary analysis. Perhaps, therefore, this study should serve to generate further hypotheses and future studies.