Validity and Reliability of the St. George's Respiratory Questionnaire in Assessing Health Status in Patients With Chronic Pulmonary Aspergillosis

Abstract

Chronic pulmonary aspergillosis (CPA) markedly reduces lung function through progressive lung destruction. To date, however, health status in patients with CPA has not been studied. This is due, in part, to a lack of adequately validated scales. The St. George's Respiratory Questionnaire (SGRQ) is widely used for several chronic respiratory diseases, but not for CPA. We examined the reliability and validity of SGRQ in CPA. Eighty-eight patients with CPA completed the SGRQ, the Short Form-36 Health Survey (SF-36), and the Medical Research Council (MRC) dyspnea scale. Lung function and BMI were also measured. Pearson correlation, t test, analysis of variance, and their equivalents for nonparametric data and multivariate linear and binary analyses were used. The SGRQ components (symptoms, activity, and impact) and total scores achieved high internal consistency (Cronbach α = 0.77, 0.91, 0.86, and 0.94), and SGRQ components had good intercorrelation (r ≥ 0.41; P < .001) and correlated well with the total score (r ≥ 0.63; P < .001). There were high, intraclass, correlation coefficients for the total SGRQ and its dimensions (≥ 0.92). The SGRQ scores showed significant correlation with the MRC dyspnea scale and SF-36 components and differentiated between all grades of shortness of breath and different bands of disease severity (P < .05). In addition, patients with greater clinician-rated disease severity had more impairment of health status (P < .006). CPA severity was independently associated with impairment in health status, and COPD comorbidity significantly affected the health status in patients with CPA. SGRQ demonstrated a significant level of reliability and validity in measuring health status in CPA.