Psychometric Properties and Prognostic Value of the UCSD Shortness of Breath Questionnaire in Hypersensitivity Pneumonitis: A Prospective Cohort Study

Rationale: Dyspnea is a prominent symptom of hypersensitivity pneumonitis (HP), limiting patients activity and impairing their quality of life. The University of California San Diego Shortness of Breath questionnaire (UCSD) is a 24-item instrument used to assess dyspnea severity in patients with various respiratory conditions. Objective: To examine the psychometric properties of the UCSD and assess the validity of its scores as measures of dyspnea severity and prognostic value in a prospective cohort with HP. Methods: We evaluated the reliability, validity, and responsiveness of UCSD scores and assessed the association between score change and survival in a cohort of patients with HP who completed the UCSD and other HP severity metrics at baseline, 6 and 12 months. We introduce the reliable change index (RCI) and the likely change index (LCI) as ways to assess the statistical significance of within-individual change in UCSD scores and conducted analyses to provide context. Results: At baseline, internal consistency (Cronbach coefficient alpha) was 0.97; there were significant, moderately strong correlations between UCSD scores and percent predicted forced vital capacity (FVC%) r = -0.39, percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) r = -0.33), and Borg dyspnea scores (0.55). UCSD scores were significantly different between the lowest and highest FVC%, 64.9 (18.9) vs. 36.2 (22.9). A 10-point worsening in the UCSD score was associated with a nearly 15-fold increase in time-to-death over the follow-up period. Conclusion: The UCSD has acceptable psychometric properties for assessing dyspnea severity in patients with HP. Worsening dyspnea is associated with shortened survival.