Statistical analysis
Sample size calculation was based on a study comparing change in BODE score 3 months post-LVRS between survivors and non-survivors at 5 years [Changes in outcome measures between groups were analysed using independent t-tests where normally distributed, otherwise the Wilcoxon rank-sum (Mann–Whitney) test was used. Treatment effect was reported as difference between means with associated 95% confidence intervals or the Hodges–Lehman estimate with its associated 95% confidence intervals. All analyses were performed according to a predefined statistical analysis plan [