Functional outcomes of clinic-based cardiac rehabilitation in patients aged ≥80 years: a 150-day comparative study

Background With the rapid ageing of populations worldwide, the prevalence of cardiovascular disease among the very elderly is increasing substantially. Although evidence regarding the effectiveness of cardiac rehabilitation (CR) in patients aged ≥80 years remains limited, particularly compared with younger individuals, CR is recognised as an essential intervention for secondary prevention and functional recovery. Purpose To evaluate the functional effects of outpatient CR in patients aged ≥80 years and to compare outcomes with those aged <80 years after 150 days. Methods We retrospectively analysed 122 consecutive patients who completed a 150-day CR programme at our community-based cardiovascular clinic between July 2022 and January 2025. We divided the cohort into a very elderly group (≥80 years, n=71) and a younger group (<80 years, n=51). Exercise capacity (anaerobic threshold oxygen uptake percentage [AT VO₂%]), physical performance (Short Physical Performance Battery [SPPB], maximum walking speed, and knee extensor muscle strength normalised to body weight), body composition (skeletal muscle mass index [SMI], fat-free mass index [FFMI], and phase angle [PhA]), fluid balance (extracellular water-to-total body water ratio [ECW/TBW]), and functional status (Kihon Checklist [KCL]) were assessed at baseline and after 150 days. Results In the very elderly group, AT VO₂% increased from 84.1±15.7% to 91.0±16.6% (p=0.002). SPPB increasing from 11.43±1.16 to 11.76±0.77 (p=0.028), maximum walking speed from 1.44±0.34 to 1.49±0.35 m/s (p=0.039) and knee extensor muscle strength from 0.47±0.14 to 0.53±0.17 kgf/kg (p<0.001). ECW/TBW decreased significantly from 0.395±0.008 to 0.394±0.008 (p=0.004). SMI and FFMI showed no significant changes, whereas PhA improved significantly from 4.41±0.63 to 4.56±0.64 (p=0.025). KCL scores improved from 6.66±4.10 to 4.97±3.59 (p<0.001), indicating amelioration of frailty-related functional status. At 150 days, there were no significant differences between the very elderly and younger groups in AT VO₂% , SPPB, or knee extensor muscle strength. In contrast, maximum walking speed (1.33±0.30 vs 1.51±0.31 m/s, p=0.001) and PhA (4.11±0.58 vs 4.56±0.64, p<0.001) remained significantly lower in the very elderly group. Conclusions Outpatient CR was associated with significant improvements in exercise capacity, physical performance, fluid balance and functional status in patients aged ≥80 years. Despite advanced age, improvements in aerobic capacity and lower limb muscle strength were comparable to those observed in younger patients after 150 days of rehabilitation. Although maximum walking speed and phase angle remained lower than in younger patients, clinically meaningful functional gains were achieved without significant changes in muscle mass indices. These findings support outpatient CR as an effective and feasible clinic-based intervention, even in very elderly patients.