ANALYSIS OF CLINICAL METHODS USED TO EVALUATE DYSPNEA IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

When dyspnea must be assessed clinically, there are three methods of a ssessment: the measurement of dyspnea with activities of daily living using clinical dyspnea ratings such as the modified Medical Research C ouncil (MRC), the Baseline Dyspnea Index (BDI), and the Oxygen Cost Di agram (OCD); the measurement of dyspnea during exercise using the Borg scale; to assess the influence of dyspnea on health-related quality o f life (HRQoL) using disease-specific questionnaires such as the St. G eorge's Respiratory Questionnaire (SGRQ) and the Chronic Respiratory D isease Questionnaire (CRQ). The purpose of the present cross-sectional study was to clarify relationships between dyspnea ratings and HRQoL questionnaires by applying factor analysis. One hundred sixty-one pati ents with mild to severe CORD completed pulmonary function tests, prog ressive cycle ergometer testing for exercise capacity, assessment of d yspnea, HRQoL, anxiety, and depression. Factor analysis demonstrated t hat the MRC, BDI, OCD, and Activity of the SGRQ, and Dyspnea of the CR Q were grouped into the same factor, and the frequency distribution hi stograms of these five measures showed virtually the same distribution . The Borg scale at the end of maximum exercise was found to be a diff erent factor. The MRC, BDI, OCD, and Activity in the SCRQ, and Dyspnea in the CRQ demonstrated the same pattern of correlation with physiolo gic data, and they had significant relationships with FEV1 (correlatio n coefficients [Rs] = 0.31 to 0.48) and maximal oxygen uptake (Rs = 0. 46 to 0.60). Disease-specific HRQoL questionnaires, the SGRQ and the C RQ. which contain a specific dimension for evaluating dyspnea, may be substituted for clinical dyspnea ratings in a cross-sectional assessme nt. Dyspnea rating at the end of exercise may provide further informat ion regarding dyspnea.