[Dyspnea grade as a prognostic factor in patients with chronic obstructive pulmonary disease]

It is known that the prognosis of patients with chronic obstructive pulmonary disease (COPD) is related to some indices of pulmonary function tests representing airway obstruction and/or the level of arterial oxygenation. Although the grade of exertional dyspnea, which is a common complaint of such patients, has also been claimed by some to be an important prognostic factor, it is not certain whether dyspnea grade is independent of other objective indices. In this study, we examined the prognosis of 97 patients with COPD in a retrospective fashion by Kaplan-Meyer's method and compared the survival time according to the dyspnea grade. As a whole, the survival time in those patients (n = 22) whose dyspnea grade initially was 4 or 5 was shorter than in patients with dyspnea grade 1 or 2 (n = 40) and dyspnea grade 3 (n = 30) (dyspnea grade 4-5 vs. dyspnea grade 1-2 and 3, p < 0.001). Since patients with higher dyspnea grades are associated with lower pulmonary function, we selected the patients whose PaO2 and forced expiratory volume in 1 second were in the same range. Dyspnea grade varied even among these subjects, and again was significantly related to the survival time. We therefore conclude that dyspnea grade, even though a subjective complaint, is an independent prognostic factor in patients with COPD.