Evaluation of the Short-Form 36-Item Questionnaire to Measure Health- Related Quality of Life in Patients With Idiopathic Pulmonary Fibrosis*

Objective: To validate the use of the 36-item short-form questionnaire (SF-36) for measuring health-related quality of life (HRQL) in patients with idiopathic pulmonary fibrosis (IPF). Design: Observational data at a single point in time. Setting: A specialized outpatient respiratory clinic. Participants: Thirty-four patients (mean 6 SE age, 58.29 6 1.87 years) with IPF and no significant comorbidity. A matched control group for HRQL measurements was composed of 34 normal subjects (mean age, 58.00 6 1.89 years). Measurements and results: Dyspnea was measured by the baseline dyspnea index (BDI). Respiratory function evaluation included FVC, FEV1, and resting arterial blood gases. IPF patients showed a mean BDI score of 5.21 6 0.46. The mean FVC and FEV1 values were 62.41 6 2.96% and 66.41 6 3.33%, respectively. The mean PaO2 was 67 6 2.51 mm Hg, and the mean PaCO2 was 37 6 1.05 mm Hg. Patients scored significantly worse than control subjects with respect to the SF-36 domains of physical functioning, physical role, general health perceptions, vitality, social functioning, emotional role, and mental health index. BDI scores were significantly correlated with five SF-36 components, and FVC and FEV1 were significantly correlated with two SF-36 components. Significant negative correlations were found between arterial pH and four SF-36 domains. Conclusions: Patients with IPF have a significant impairment of HRQL in both physical and psychological functioning. Dyspnea is the most important factor influencing the quality of life in these subjects. The SF-36 questionnaire is a valid instrument to evaluate HRQL in IPF patients. (CHEST 2000; 117:1627–1632)