OBJECTIVES: A popular approach to estimate treatment effects is the meta-analysis of individual participant data (IPD). This study aimed to assess through IPD the impact of exercise-based cardiac rehabilitation (ExCR) on exercise capacity and health-related quality of life (HRQoL) and identify subgroups of patients with heart failure (HF) that may respond differently to ExCR.

METHODS: The Exercise Training Meta-Analysis of Trials for Chronic Heart Failure (ExTraMATCH II) collected IPD from RCTs that compared exercise rehabilitation with a non-exercise control and a minimum follow-up of 6 months. Outcomes of interest were the 6 Minutes Walk Test (6MWT), peak volume of oxygen consumption (pVO), the Minnesota Living with Heart Failure (MLHF) or other HRQoL questionnaires. The primary analyses included one-stage and two-stage IPD meta-analyses carried out at 6 and 12 months. All primary analyses used IPD hierarchical random effects regression models, adjusted for the baseline value of the outcome measure.

RESULTS: Thirteen studies provided anonymised IPD for 3,000 patients (1,496 ExCR, 1,504 control) with a median follow-up of 33 weeks. Compared to control, average treatment effects from the one-stage meta-analysis over 12 months showed a significant improvement in MLHF: 5.94 (95% CI 1.0 to 10.9), standardised HRQoL score: 0.20 (95% CI 0.03 to 0.37), 6MWT: 21.0 (95% CI 1.57 to 40.4) and standardised exercise capacity score: 0.27 (95% CI 0.11 to 0.43) for patients assigned to ExCR. No significant difference in peak VO2 was observed: 1.01 (95% CI -0.42 to 2.44). Interaction analyses revealed no consistent interaction between the effect of ExCR and the predefined subgroups.

CONCLUSIONS: Access to individual data from several RCTs allows to address important questions on the benefits of ExCR in HF failure. Results from this IPD must be discussed in light of findings from previous aggregate data meta-analyses on the same topic.