Assessment of fatigue and dryness in primary Sjögren's syndrome: Brazilian version of "Profile of Fatigue and Discomfort - Sicca Symptoms Inventory (short form) (PROFAD-SSI-SF)"

Objective: 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.

Method: 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).

Results: 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.

Conclusion: The Portuguese version of PROFAD-SSI-SF proved to be an adaptable, reproducible and valid tool for the Brazilian Portuguese language.