Validity of Two New Patient-Reported Outcome Measures in Systemic Sclerosis: Patient-Reported Outcomes Measurement Information System 29-Item Health Profile and Functional Assessment of Chronic Illness Therapy-Dyspnea Short Form

Objective. Many patient-reported outcome (PRO) instruments used in systemic sclerosis (SSc) trials are limited by lack of validation, licensing fees, and complicated scoring systems. We assessed the construct validity for discriminative purposes of 2 new PRO instruments, the Patient-Reported Outcomes Measurement Information System 29-item Health Profile (PROMIS-29) and the Functional Assessment of Chronic Illness Therapy-Dyspnea short form (FACIT-Dyspnea), measuring health status and dyspnea in SSc patients. Methods. Seventy-three patients participated in a cross-sectional study at a tertiary SSc program. PROMIS-29, FACIT-Dyspnea, and legacy PRO instruments used in clinical trials (Medical Research Council Dyspnea Score, St. George's Respiratory Questionnaire, Health Assessment Questionnaire disability index, and Short Form 36) were administered. Composite severity scores using an adaptation of the Medsger Disease Severity Index were generated using clinical, diagnostic, and laboratory information. PROMIS-29 and FACIT-Dyspnea scores were compared with legacy PRO measures and composite severity scores. Results. The mean patient age (84% women) was 51 years (range 22-72 years). The mean SSc disease duration from the onset of the first non-Raynaud's phenomenon symptom was 7.2 years (range 0-45 years). Spearman's correlation coefficients across FACIT-Dyspnea and PROMIS physical functioning scores with legacy PRO instruments were generally high (range 0.50-0.86); those between PROMIS and FACIT-Dyspnea with composite disease severity scores were more modest, but statistically significant (range 0.33-0.48, P < 0.01). Conclusion. PROMIS-29 and FACIT-Dyspnea are valid instruments to measure the health status of SSc patients. PROMIS-29 and FACIT-Dyspnea may be preferable to legacy instruments because they are freely available in multiple languages and simple to administer, score, and interpret.