Psychometric Evaluation of the National Institutes of Health Patient-Reported Outcomes Measurement Information System in a Multiracial, Multiethnic Systemic Lupus Erythematosus Cohort

Abstract

Objective: We examined psychometric performance of Patient-Reported Outcomes Measurement Information System (PROMIS) measures in a racially/ethnically and linguistically diverse cohort with systemic lupus erythematosus (SLE). Methods: Data were from the California Lupus Epidemiology Study, a multiracial/multiethnic cohort of individuals with physician-confirmed SLE. The majority (n = 332) attended in-person research visits that included interviews conducted in English, Spanish, Cantonese, or Mandarin. Up to 12 PROMIS short forms were administered (depending on language availability). An additional 99 individuals completed the interview by phone only. Internal consistency was examined with Cronbach's alpha and item-total correlations. Correlations with the Short Form 36 subscales and both self-reported and physician-assessed disease activity assessed convergent validity. All analyses were repeated within each racial/ethnic group. Differences in scores by race/ethnicity were examined in bivariate analyses and by multiple regression analyses controlling for age, sex, disease duration, and disease damage and activity. Results: The total sample was 30.0% white, 22.3% Hispanic, 10.9% African American, 33.7% Asian, and 3.0% other race/ethnicity. Seventy-seven percent of interviews were conducted in-person. Non-English interviews were conducted in 26.0% of the Hispanic subjects and 18.6% of the Asian subjects. Each scale demonstrated adequate reliability and validity overall and within racial/ethnic groups. Minimal floor effects were observed, but ceiling effects were noted. Missing item responses were minimal for most scales, except for items related to work. No differences were noted by mode of administration or by language of administration among Hispanics and Asians. After accounting for differences in disease status, age, and sex, few differences in mean scores between whites and other racial/ethnic groups were noted. Conclusion: PROMIS measures appear reliable and valid in persons with lupus across racial/ethnic groups.