Sixteen trials were included in the review and 14 trials were included in the meta-analysis, with a total of 478 patients. Maximum exercise capacity was measured in 11 trials (309 patients), functional exercise capacity was measured in 11 trials (413 patients) and HRQL was measured using a valid instrument in 6 trials (number of patients not stated).
Maximum exercise capacity:
Pooled effect size was statistically-significant (0.3 SD units, 95% CI: 0.1, 0.6) which corresponded, in incremental cycle ergometer test units, to 8.3 W (95% CI: 2.8, 16.5). Test for heterogeneity was not statistically-significant (p=0.85).
Functional exercise capacity:
Converting back to natural units for the 6-minute walk test (metre 'm'), the difference in response between the treatment and control group was 55.7 m (95% CI: 27.8, 92.8). The limits of the confidence intervals (27.8 to 92.8) were wider than the estimated MCID (37-71m). There was significant heterogeneity among study results (p=0.0008) that could not be explained by subgroup analysis. Post hoc analysis showed a significant difference between programmes of 6 months' duration and the other programme (93m vs 39.2m; difference, p=0.0004).
Health related quality of life (HRQL):
For dyspnoea (breathing difficulty) and mastery, the overall treatment effect size was larger than the MCID:1.0 (95% CI:0.6,1.5) and 0.8 (95% CI:0.5, 1.2) respectively, compared with a MCID of 0.5.