ABSTRACT
Abstract Background Diagnosis of SS is a complex task, as no symptom or test is unique to this syndrome. The American-European Consensus Group (AECG 2002) and the American-European classification criteria of 2016 (ACR/EULAR 2016) emerged through a search for consensus. This study aims to assess the prevalence of Sjögren's Syndrome (SS) in patients with Systemic Lupus Erythematosus (SLE), according to AECG 2002 and ACR-EULAR 2016 classifications, as well as clinical and histopathological features in this overlap. To date, there is no study that has evaluated SS in SLE, using the two current criteria. Methods This cross-sectional study evaluated 237 SLE patients at the outpatient rheumatology clinic between 2016 and 2018. Patients were submitted to a dryness questionnaire, whole unstimulated salivary flow (WUSF), "Ocular Staining Score" (OSS), Schirmer's test I (ST-I), and labial salivary gland biopsy (LSGB). Results After verifying inclusion and exclusion criteria, a total of 117 patients were evaluated, with predominance of females (94%) and mixed ethnicity (49.6%). The prevalence of SS was 23% according to AECG 2002 and 35% to ACR- EULAR 2016. Kappa agreement between AECG 2002 and ACR-EULAR 2016 were 0.7 (p < 0.0001). After logistic regression, predictors for SS were: anti/Ro (OR = 17.86, p < 0.05), focal lymphocytic sialadenitis (OR = 3.69, p < 0.05), OSS ≥ 5 (OR = 7.50, p < 0.05), ST I positive (OR = 2.67, p < 0.05), and WUSF ≤ 0.1 mL/min (OR = 4.13, p < 0.05). Conclusion The prevalence of SS in SLE was 23% (AECG 2002) and 35% (ACR-EULAR 2016). The presence of glandular dysfunction, focal lymphocytic sialadenitis, and anti/Ro were predictors of SS in SLE. The greatest advantage of the new ACR-EULAR 2016 criteria is to enable an early diagnosis and identify the overlapping of these two diseases. ACR- EULAR 2016 criteria is not yet validated for secondary SS and this study is a pioneer in investigating prevalence based on the new criteria.