Using possible predictors derived from key measurements collected from cardiopulmonary exercise testing (CPET), improved predictors of early death in patients with chronic obstructive pulmonary disease (COPD) were identified by the researchers for a study. It was prospective cohort research that followed 126 COPD patients for 42 months. The clinical examination was followed by a pulmonary function test and CPET for each subject. CPET was done on a cycle ergometer with electromagnetic braking, and ventilatory expired analysis was done breath per breath with a computer-based system. Peak oxygen consumption (V̇O2, mlO2. kg−1. min−1), minute ventilation/carbon dioxide production, and the slope (V̇E/V̇CO2) were acquired using CPET. 

During the 42-month follow-up, 48 patients (38%) died. A V̇E/V̇CO2 slope of ≥30, a peak V̇E ≤ 25.7L/min, and a peak V̇O2 of ≤ 13.8 mlO2. kg−1. min−1 were all major predictors of death in COPD patients, according to a Kaplan Meier analysis. The major predictors of mortality risk were the V̇O2 peak of ≤ 13.8 mlO2. kg−1. min−1 (CI 95% 0.08–0.93), V̇E/V̇CO2 slope ≥30 (CI 95% 0.07–0.94), V̇E peak ≤25.7 L/min (CI 95% 0.01–0.15), Sex (CI 95% 0.04–0.55), and Age (CI 95% 1.03–1.2). Reduced exercise capacity, peak ventilation, and ventilatory inefficiency were all independent prognostic indicators. CPET, like in patients with heart failure, maybe a useful clinical evaluation in the COPD group.