Health-related Quality of Life in Patients with Idiopathic Pulmonary Fibrosis - Cross-sectional and Longitudinal Study

Object To validate the cross-sectional and longitudinal use of the Medical Outcome Study Short Form 36 (SF-36) for measuring health-related quality of life (HRQL) in patients with idiopathic pulmonary fibrosis (IPF). Methods Patients were administered the SF-36 and concomitantly underwent laboratory and physiologic tests and high-resolution computed tomography (HRCT). Forty-six patients participated in the initial cross-sectional study, and 32 patients who were available more than one year later again underwent these studies under the same conditions. Results Patients with IPF had significantly lower scores across all 8 domains of the SF-36 when compared with the general population. Significant decline of HRQL was observed in 2 physical domains. There were significant differences in within-subject changes in a few domains according to worsening of the physiologic parameters. Vital capacity as percent of predicted was significantly correlated with the results of 6 subscales and its changes were significantly correlated with those of 4 subscales. The 6-min-walk distance was correlated significantly with 3 subscales and its changes were significantly correlated with those of 4 subscales. Changes in the HRCT ground-glass score were significantly correlated with those of 3 subscales. No significant correlations between changes in 3 domains and those of any clinical parameters were observed. Conclusion Patients with IPF had significantly impaired HRQL in both physical and psychological functions. This disease clearly decreased the physical aspects of HRQL over time. HRQL instruments should be incorporated into routine evaluations of IPF patients, since they measure dimensions not fully estimated by clinical assessment.