Objective: The University of California in San Diego Shortness of Breath Questionnaire (UCSD SOBQ) has been used to assess dyspnea-related activity limitation in patients with airway and parenchymal lung disease. We sought to assess the construct validity and responsiveness of the UCSD SOBQ in systemic sclerosis (SSc; scleroderma) patients with incident pulmonary hypertension (PH) and those at high risk of developing PH.
Methods: We used data from 179 patients enrolled in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma Registry with pre-PH (defined by criteria on pulmonary function tests and/or echocardiogram) or definite PH with mean pulmonary artery pressure ≥25 mm Hg by right-sided heart catheterization within 6 months of enrollment. For this analysis, we included those subjects with complete data for self-reported measures at baseline and at 12 months.
Results: At baseline, the UCSD SOBQ had strong correlations in the expected direction with the disability index (DI) of the Health Assessment Questionnaire (HAQ) (r = 0.71, P < 0.0001), dyspnea assessment by visual analog scale (r = 0.71, P < 0.0001), and the Short Form 36 (SF-36) health survey physical component summary (PCS) score (r = -0.77, P < 0.0001), as well as a moderate correlation with the 6-minute walk test distance (r = -0.33, P < 0.0001), Borg dyspnea score (r = 0.47, P < 0.0001), and diffusing capacity of carbon monoxide (r = -0.33, P < 0.0001). Change in the UCSD SOBQ at 12 months correlated in the expected direction with change in the HAQ DI (r = 0.54, P < 0.0001) and change in the SF-36 PCS (r = -0.44, P < 0.0001). Multivariate analysis adjusting for age, sex, and race identified male sex as a significant predictor of death (odds ratio [OR] 7.00, 95% confidence interval [95% CI] 1.55-31.76), while the UCSD SOBQ showed a strong trend toward significance (OR 1.82, 95% CI 0.97-3.41).
Conclusions: The UCSD SOBQ demonstrates good construct validity and responsiveness to change in SSc patients with pulmonary vascular disease.
Copyright © 2013 by the American College of Rheumatology.