Characteristics of pulmonary rehabilitation programmes and their effects on exercise capacity and quality of life in patients with interstitial lung diseases: a systematic review and meta-analysis

Background: Interstitial Lung Disease (ILD) is mainly characterised by dyspnoea, reduced exercise capacity (EC) and poor quality of life (QoL). Although increasing, the evidence to support the benefits of pulmonary rehabilitation (PR) on both EC and QoL in this population is still limited. Aim: The aim of this study is to identify the component of PR with the most effect on both EC and QoL. Methods: We searched in 5 different databases (PubMed, CINAHL, Cochrane, PEDro, and EMBASE) from January 1990 to July 2022 using a PICOS [Population: ILD patients; Intervention: PR; Comparison: no PR; Outcomes: EC measured via six-minute walk distance (6MWD) and QoL via the St George’s respiratory questionnaire (SGRQ); Study type: only randomized controlled trials (RCTs)] search strategy. We used the Cochrane risk-of-bias tool and GRADE approach to rate the quality of the evidence. Results: We identified 11 RCTs (476 ILD patients; 8 countries). 10 studies provided numerical data for 6MWD and 7 studies for SGRQ. Both 6MWD and SGRQ improved ≥ their respective MCID of 45m and 7 units in studies where PR were i) ˃8 weeks (n=5) [6MWD: MD 58m, 95% CI 37 to 79, p<0.00001; SGRQ: MD -9.7, 95% CI -12.6 to -6.7, p<0.00001], ii) incorporated high-intensity interval training (HIIT) (n=2) [6MWD: MD 77m, 95% CI 45 to 109, p<0.00001; SGRQ: MD -10.3, 95% CI -13.7 to -6.9, p<0.00001] and iii) fully supervised [6MWD (n=5): MD 53.6m, 95% CI 39 to 68, p<0.00001; SGRQ (n=2): MD -9.38, 95% CI -12.93 to -5.84, p<0.00001]. Conclusion: PR programmes of ˃8 weeks, with HIIT and fully supervised had a better impact on EC and QoL.