Interindividual response variation to exercise-based cardiac rehabilitation on changes in cardiorespiratory fitness in heart transplant patients: A secondary meta-analysis of randomized controlled trials

Abstract

PurposeDetermine whether true inter-individual exercise response differences (IIRD) occur in cardiorespiratory fitness (CRF) as a result of exercise-based cardiac rehabilitation in heart transplant patients. MethodsUsing data from a recent (2023) meta-analysis of nine RCTs representing 296 patients (163 exercise, 133 control), an aggregate data meta-analysis of treatment effects (change outcome differences between exercise and control groups) was conducted as well as an IIRD meta-analysis using the inverse variance heterogeneity (IVhet) model. The primary outcome was cardiorespiratory fitness (VO2max) in mL.kg-1.min-1. ResultsStatistically significant and clinically important increases equivalent to 14.5% were observed for VO2max in mL.kg-1.min-1 (X̅, 3.0, 95% CI, 2.4 to 3.7 mL.kg-1.min-1, p <0.001; Q=11.8, p=0.16; I2=32.0%, 95% CI, 0% to 68.8%; τ2=0.4). The 95% prediction interval (PI) was 1.2 to 4.7 mL.kg-1.min-1. However, no statistically significant IIRD were observed (X̅, 0.6, 95% CI, -1.1 to 1.4 mL.kg-1.min-1; τ2=2.9). The 95% PI was -2.7 to 2.8 mL.kg-1.min-1. ConclusionsWhile exercise-based cardiac rehabilitation increases VO2max in mL.kg-1.min-1 in heart transplant patients, a lack of true exercise-associated IIRD exist. A need exists for additional well-designed randomized controlled trials of longer duration to determine the long-term effects of exercise-based cardiac rehabilitation on VO2max in mL.kg-1.min-1 among heart transplant patients.