Diagnostic performance of dry eye tests, serology and labial salivary gland biopsy in primary Sjogren's syndrome in an Indian setting

Abstract

PurposeTo evaluate the diagnostic performance of dry eye tests, serology and labial salivary gland biopsy in Primary Sjogren's syndrome (pSS). MethodsProspective cross-sectional study spanning 7-months of patients referred from rheumatology for evaluation of dry eyes. Severity of ocular symptoms was assessed using the Ocular Surface Disease Index (OSDI) questionnaire. The sensitivity, specificity and positive likelihood ratio (+LR) of Schirmer-I (Sch-I) test, Tear Break-up time (TBUT) and Ocular Staining Score (OSS) were assessed and Receiver Operating characteristic (ROC) curves were analysed. The American College of Rheumatology (ACR) criteria was used to diagnose pSS. ResultsOf the 95 patients, 31 (32.6%) fulfilled the ACR criteria for pSS. OSDI score was significantly (p < 0.001) higher (24.6 ± 9.4) in pSS than non-pSS (17.8 ± 5.4) patients. The sensitivity and specificity were 3.2% and 100% for Sch-I ≤5 mm and 61.3% and 90.6% for OSS ≥3 respectively. TBUT of <10 s had poor specificity (12.5%); however at lower threshold (<8 s), sensitivity (80.6%) and specificity (60.9%) were optimal. The + LR was 2.07 for TBUT <8 s and 6.54 for OSS ≥3. Twenty-six (83.9%) patients diagnosed as pSS had anti-SSA or anti-SSB antibodies. Anti-SSA, when compared with anti-SSB, had better sensitivity (76.7% vs. 52.4%) than specificity (88.7% vs. 100%). Labial biopsy had the best diagnostic performance (sensitivity 96.8%; specificity 88.9%; +LR 8.71). ConclusionIn patients with high OSDI scores, dry eye tests in combination with serology will identify the subset of patients with a high probability of pSS. Labial biopsy may be considered in patients with negative serology.