Study objective: To examine the relationship among clinical dyspnea ratings, physiologic pulmonary function, and general health status in symptomatic patients with chronic obstructive pulmonary disease (COPD).
Design: Observational data collected at a baseline state.
Setting: Outpatient pulmonary disease clinics at a university hospital and two VA medical centers.
Patients: One hundred ten male patients with COPD with no significant comorbidity were recruited.
Measurements and results: Clinical ratings of dyspnea were measured by the multidimensional baseline dyspnea index (BDI). Pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximal inspiratory mouth pressure (PImax). General health status was assessed with the Medical Outcomes Study short-form survey, which consists of 20 questions that cover six health components. The mean age of the patients was 67 +/- 8 yr (+/- SD). The mean value for FVC was 2.84 +/- 0.84 L (68 +/- 18 percent of predicted), for FEV1 was 1.28 +/- 0.59 L (44 +/- 17 percent of predicted), and for PImax was 59.0 +/- 25.0 cm H2O. The BDI score and PImax were significantly correlated with five of the six components of general health status. Only three of the six components of general health were significantly correlated with FEV1 as percent predicted (rs value range, 0.30 to 0.44) and with FVC as percent predicted (rs value range, 0.25 to 0.33). Statistical comparisons showed that the BDI score had significantly higher correlations than FVC (percent predicted), FEV1 (percent predicted), and PImax values with physical functioning and role functioning. Multiple linear regression analysis showed that the BDI score was the only statistically significant predictor of role functioning, mental health, and health perceptions for general health status, whereas both the BDI score and FEV1 (percent predicted) were independent predictors of physical functioning and social functioning.
Conclusion: Dyspnea ratings influence and predict general health status to a greater extent than do physiologic measurements in symptomatic patients with COPD. A shift in focus from the pathophysiology of disease to assessment and relief of symptoms may provide more meaningful benefits for the individual patient in terms of quality of life. This consideration requires that health-care providers use available measuring tools in clinical practice to quantify symptoms, as well as overall health status.