COMPARISON OF DISCRIMINATIVE PROPERTIES AMONG DISEASE-SPECIFIC QUESTIONNAIRES FOR MEASURING HEALTH-RELATED QUALITY-OF-LIFE IN PATIENTS WITHCHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Three disease-specific, health-related quality of life (HRQL) question naires have been introduced to assess patients with chronic obstructiv e pulmonary disease (COPD): the St. George's Respiratory Questionnaire (SGRQ), the Breathing Problems Questionnaire (BPQ), and the Chronic R espiratory Disease Questionnaire (CRQ). The purpose of the present stu dy was to make comparisons between the SGRQ, the BPQ, and the CRQ in t heir discriminative properties, and to clarify the characteristics of each questionnaire. One hundred forty-three patients with mild to seve re COPD completed pulmonary function tests, progressive cycle ergomete r testing for exercise capacity, assessment of dyspnea, anxiety, and d epression, and assessment of HRQL. The frequency distributions of the questionnaire scores showed that the SGRQ and the CRQ were normally di stributed and that the BPQ was skewed toward low scores. Relationships between all dimensions of the three questionnaires were significant ( correlation coefficients [Rs] = 0.74 to 0.86). The three questionnaire s had significant but weak correlations (Rs = -0.24 to -0.36) with som e physiologic variables (VC, FEV1, and DLCO/Va) and mild to moderate c orrelations with exercise capacity and assessment of dyspnea, anxiety, and depression. Stepwise multiple regression analyses revealed that t he Baseline Dyspnea Index (BDI) score, anxiety by the Hospital Anxiety Depression Scale (HAD), and maximal oxygen uptake ((V) over dot O(2)m ax) accounted for 61% of the variance in the SGRQ and that the BDI and anxiety of the HAD accounted for 53 and 49% of the variance in the BP Q and the CRQ, respectively. Dyspnea and psychologic status impacted t he HRQL in patients with COPD. Although no substantial differences bet ween the SGRQ, the BPQ, and the CRQ were evident in the correlations w ith physiologic parameters and the influential factors, the BPQ was fo und to be less discriminatory than the SGRQ and the CRQ in evaluating HRQL cross-sectionally.