To perform a cross-cultural adaptation and validation of the Profile of Fatigue and Discomfort - Sicca Symptoms Inventory (short form) (PROFAD-SSI-SF) questionnaire assessing the subjective aspects of the symptoms of primary Sjögren syndrome (pSS), for the Brazilian Portuguese language.
Conceptual, of the item, semantic and operational equivalences were evaluated. The Brazilian version of PROFAD-SSI-SF was administered to 62 women with pSS according to the European-American consensus 2002 to assess measurement equivalence. α-Cronbach was used for internal consistency; intraclass correlation coefficient (ICC) for intraobserver reproducibility; and Spearman correlation coefficient for validity by comparing with Patient Global Assessment (PaGA), EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI), Functional Assessment of Chronic Illness Therapy Fatigue Subscale (FACIT-F) and EuroQOL (EQ-5D).
The internal consistency of PROFAD, SSI and total score was 0.80; 0.78; and 0.87, respectively. The intraobserver reproducibility of total PROFAD was 0.89; of total SSI of 0.86; and total score of 0.89. In terms of validity, PROFAD correlated significantly with PaGA (r = 0.50), FACIT-F (r = 0.59), ESSPRI (r = 0.58) and all domains of EQ-5D, with the exception of Mobility. On the other hand, SSI correlated significantly with PaGA (r = 0.43), FACIT-F (r = 0.57), ESSPRI (r = 0.55) and most areas of EQ-5D. The total score of PROFAD-SSI-SF had a non-statistically significant correlation only with Mobility domain and with 1-100 range of EQ-5D.
The Portuguese version of PROFAD-SSI-SF proved to be an adaptable, reproducible and valid tool for the Brazilian Portuguese language.