Cardiorespiratory fitness in COPD and HF from the Fitness Registry and the Importance of Exercise: a National Database

Aims: To better characterize functional consequences of the presence of COPD on cardiorespiratory fitness in patients with HF.

Methods and results: Patients with any clinical indication for cardiopulmonary exercise testing (CPET) were included in the international FRIEND registry. Diagnosis of COPD was confirmed by a ratio of forced expiratory volume in 1 s and forced vital capacity (FEV₁/FVC) < 0.70. HF was diagnosed in the presence of symptoms and signs of HF. A total of 10 957 patients were divided into four groups: patients without HF or COPD (n = 8963), patients with HF (n = 852) or COPD (n = 991) alone, and patients with both HF and COPD (n = 151). Maximal workload was the lowest in patients with both HF and COPD [78.09 (95% CI: 72.92, 83.64 watts)], and all pairwise comparisons with adjusted P < 0.05 between groups were statistically significant. Patients with both HF and COPD yielded the lowest PETCO₂ values [31.80 (95% CI: 31.00, 32.60)] mmHg and exhibited a higher VE/VCO₂ slope compared with HF (36.73 (95% CI: 35.78, 37.68) vs. 33.91 (95% CI: 33.50, 34.33 units, P < 0.0001). Peak VO₂ was the lowest with concomitant HF and COPD 19.93 (95% CI: 18.60, 21.27) mL/kg/min and was significantly different compared with all other groups (P < 0.05).

Conclusion: Patients referred for CPET with COPD and concomitant HF exhibit a profound impairment in CRF compared with patients with COPD or HF alone. Early identification of pulmonary obstruction in patients with HF by more frequent usage of pulmonary function testing may contribute to providing better treatment for both COPD and HF in these high-risk individuals.