Reliability and validity of modified pulmonary functional status and dyspnea questionnaire in Chinese patients with chronic obstructive pulmonary disease

Abstract

To determine the reliability and validity of the modified pulmonary functional status and dyspnea questionnaire (PFSDQ-M) Chinese version in patients with chronic obstructive pulmonary disease (COPD) at 2 hospitals in Beijing, China. PFSDQ-M has three domains, i.e., change experienced by patient with activities or activity restriction (CA), dyspnea with activities (DA) and fatigue with activities (FA). Sixty-one patients with COPD in stable condition were assessed by interview with PFSDQ-M Chinese version, modified Medical Research Council dyspnea scale (MMRC), respectively, and underwent pulmonary function test (PFT) and 6-minute walking test (6MWT) on the same day or within one week before interview. Cronbach's alpha was 0.84, 0.85 and 0.89 for domains of CA, DA and FA of the PFSDQ-M, respectively. Scores of change in activities, dyspnea and fatigue with activities in patients of COPD correlated to their 6-minute walking distance (r = -0.39 to -0.50), FEV(1) (r = -0.28 to -0.36), FEV(1)/FVC (r = -0.27 to -0.37), FEV(1)% of predicted (r = -0.27 to -0.37), dyspnea score in MMRC (r = 0.59 to 0.66) and BODE index (r = 0.40 to 0.51), respectively (all P < 0.01). Degrees of restriction of activity, dyspnea and fatigue with activities varied significantly in patients with different severity of COPD (chi(2) = 7.35 to 15.21, P < 0.05, P < 0.01, respectively). Results of 61 patients with COPD interviewed with PFSDQ-M Chinese version suggest its good reliability and validity in discriminating patients with COPD of varied severity and stages.