Assessment of health-related quality of life in patients with interstitiallung disease

Study objectives: Health-related quality of life associated with interstiti al lung disease has received little attention in clinical studies because t here have been no validated methods for directly measuring it. We have asse ssed the validity of several generic and respiratory-specific quality-of-li fe instruments in patients with interstitial lung disease. Design: Cross-sectional study. Setting: Outpatient pulmonary clinic at a university referral center. Patients: Fifty patients with interstitial disease such as idiopathic pulmo nary fibrosis, sarcoidosis, hypersensitivity pneumonitis, and asbestosis. Interventions: Patients were administered four quality-of-life questionnair es, the Medical Outcomes Study Short Form 36 (SF-36), the Quality of Well-b eing scale (QWB), the Chronic Respiratory Questionnaire (CRQ), and the St. George's Respiratory Questionnaire (SGRQ), Patients concomitantly underwent pulmonary function testing and performed a 6-min walk, Measurements and results: Validation of these instruments was based on test ing an a priori hypothesis that worse quality-of-life scores should correla te with more severe physiologic impairment demonstrated by pulmonary functi on tests, exercise tolerance on the 6-min walk, and dyspnea scores. Our pat ients, on average, had a moderate degree of physiologic impairment and demo nstrated moderately decreased duality-of-life scores. Scores from all four quality-of-hfe questionnaires correlated significantly with 6-min walk dist ance and dyspnea score. Scores from the SF-36, QWB, and SGRQ showed signifi cant correlation with FVC, FEV1, and diffusing capacity as well. The SF-36 and SGRQ consistently showed the strongest correlation with physical impair ment. Conclusions: Our findings indicate that preexisting quality-of-life instrum ents can be applied to patients with interstitial lung disease and suggest that the SF-36 and the SGRQ, in particular, are sensitive tools for assessi ng quality of life in these patients. Future intervention studies of patien ts with interstitial lung disease should consider using these measures.