Maximal oxygen uptake cannot be estimated from resting lung function and submaximal exercise in patients with chronic obstructive pulmonary disease.

Background: Maximal oxygen uptake ((V)O(2max)) obtained from incremental exercise testing is a useful indicator of limited exercise capacity. Several prediction equations have been developed to estimate (V)O(2max) in patients with chronic obstructive pulmonary disease (COPD), but agreement studies between estimated and measured (V)O(2max) are lacking. This study aims to assess agreement between the 6 estimated (V)O(2max) evaluated during maximal incremental exercise testing in male COPD patients.

Methods: Patients with stable COPD, in accordance with GOLD guidelines, were included in the study. Agreement between (V)O(2max) obtained during incremental exercise testing and (V)O(2max) obtained from 6 prediction equations were studied. To estimate (V)O(2max) from anthropometric prediction equations, lung function variables and submaximal exercise testing were used.

Results: Of the 60 male patients in the study, 12 were GOLD stage II, 24 GOLD stage III, and 24 GOLD stage IV. Five prediction equations underestimated the value of (V)O(2max) in relation to measured (V)O(2max) : equations 1, 2, 3, 4, and 6, by 14%, 66%, 42.2%, 35%, and 23.3%, respectively. Conversely, prediction equation 5 overestimated measured (V)O(2max) by 76.9%. Agreement between all (V)O(2max) prediction equations and measured (V)O(2max) was poor. Discrepancy between (V)O(2max) prediction equations and measured (V)O(2max) varied from 20.857 to 0.736 L/min.

Conclusions: The use of lung function at rest and submaximal exercise testing is inaccurate for determining (V)O(2max) , which cannot be estimated by prediction equations in patients with stable COPD.