From the Authors

From the authors:

We are pleased to respond to the comments made by C.K. Connolly. We completely agree with the need to dissociate disability from dyspnoea in the clinical assessment of the chronic obstructive pulmonary disease (COPD) patient. Dyspnoea can arise from many inputs, and, while it correlates with airflow limitation, it does so relatively poorly. Dyspnoea can limit performance. We agree with the suggestion that evaluation of exercise performance can assist in the evaluation of COPD patients. Muscle weakness, however, is a better predictor of disability in COPD than airflow, and this weakness may be due not only to detraining, but also to the inflammatory processes and circulating cytokines that characterise some COPD patients. Because of this latter point, we disagree with C.K. Connolly's suggestion that disability in COPD must be related to the measurable forced expiratory volume in one second (or flow/volume loop) abnormalities.

Clearly the chronic obstructive pulmonary disease patient's clinical status reflects not only the impaired airflow, but also other pulmonary and systemic aspects of the disease. We doubt the disease is underdiagnosed; our survey, in fact, focused on diagnosed cases. Among those individuals, we have little doubt that it is underevaluated. C.K. Connolly's suggestion that more aggressive assessment of objective measures in the chronic obstructive pulmonary disease patient is needed is one with which we wholeheartedly agree. More aggressive identification of the undiagnosed individuals will also be important.