Patient-Reported Dyspnea Correlates Poorly with Aerobic Exercise Capacity Measured During Cardiopulmonary Exercise Testing

Background Patient-reported dyspnea plays a central role in assessing cardiopulmonary disease. There is little evidence, however, that dyspnea correlates with objective exercise capacity measurements. If the correlation is poor, dyspnea as a proxy for objective assessment may be misleading. Objective To compare patient’s perception of dyspnea with maximum oxygen uptake (MaxVO2) during cardiopulmonary exercise testing (CPET). Methods Fifty patients undergoing CPET for dyspnea evaluation were studied prospectively. Dyspnea assessment was measured by a metabolic equivalent of task (METs) table, Mahler Dyspnea Index, Borg Index, number of blocks walked, and flights of stairs climbed before stopping due to dyspnea. These descriptors were compared to MaxVO2. Results MaxVO2 showed low correlation with METs table ( r = 0.388, p = 0.005) and no correlation with Mahler Index ( r = 0.24, p = 0.093), Borg Index ( r = −0.017, p = 0.905), number of blocks walked ( r = 0.266, p = 0.077) or flights of stairs climbed ( r = 0.188, p = 0.217). When adjusted for weight (maxVO2/kg), there was significant correlation between MaxVO2 and METs table ( r = 0.711, p