INTRODUCTION: The EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) is an index of primary Sjögren's syndrome (PSS) systemic activity. OBJECTIVE: To perform the ESSDAI transcultural adaptation into Brazilian Portuguese. METHOD: This was a cross-sectional study with 62 patients with PSS according to the criteria of the 2002 American-European Consensus. Six stages were conducted: conceptual, item, semantic, operational, functional, and measurement equivalences (interobserver reproducibility and construct validity). For the validity assessment, the ESSDAI was compared with the Physician's Global Assessment (PhGA), the Sjögren's Syndrome Disease Activity Index (SSDAI), and the Sjögren's Systemic Clinical Activity Index (SCAI). Patients were classified by a specialist physician into two groups according to disease activity (active and inactive), and according to the intention-to-treat (increase in therapy and no increase in therapy). The ESSDAI was tested in these groups. The following statistical tests were used: intraclass correlation coefficient (ICC), Bland-Altman plot for reproducibility, and Spearman's correlation coefficient (r s) and Mann-Whitney's test for validity (P < 0.05 and 95% CI). RESULTS: The mean ESSDAI score was 4.95 ± 6.73. The reproducibility obtained a strong ICC of 0.89 and good agreement. When compared with other indices, it showed a strong r s with PhGA (0.83; P < 0.000), a moderate r s with SSDAI (0.658; P < 0.000) and a weak r s with the SCAI (0.411; P = 0.001). The group "active" and the group " increase in therapy" had higher ESSDAI values (P = 0.000). CONCLUSION: The Brazilian Portuguese version of ESSDAI was shown to be adaptable, reproducible, and valid for this language.
Sjögren's syndrome; Scales; Validation studies; ESSDAI
