Background Sjögren's syndrome (SS) is generally diagnosed on the basis of objective criteria, including xerophthalmia, xerostomia, autoantibodies, and labial salivary gland biopsy. Patients without objective sicca symptoms (non-sicca SS) require a biopsy. For such patients, we should evaluate pretest probability using parameters other than sicca symptoms before performing an invasive biopsy. To assess pretest probability, data on clinicopathological characteristics of non-sicca SS are needed.

Objectives This study aimed to analyze the clinicopathological features of non-sicca SS. Epidemiological data, antibody profiles, organ involvement, and labial salivary gland biopsy results in non-sicca SS patients were compared with those in SS patients with objective sicca symptoms (sicca SS).

Methods We selected 103 patients with primary SS who met Japanese or American College of Rheumatology criteria; those whose results exceeded the focus score by 1 underwent salivary gland biopsy. Objective xerophthalmia was evaluated with the Schirmer's test, and objective xerostomia with the Saxon's test. Seventeen patients were excluded because neither test was performed. Sicca SS was defined as a positive Schirmer's and/or Saxon's test result. Clinical and laboratory data were compared in 70 sicca SS and 16 non-sicca SS patients.

Results Non-sicca SS patients were younger at diagnosis (45.9±14.8 vs. 61.4±15.1 years, p<0.001), had a shorter disease duration (1.1±1.5 vs. 6.9±8.9 years, p<0.001), and had a higher rate of positive anti-SS-A/Ro antibody (100 vs. 74.3%, p=0.023), and a lower rate of positive anti-centromere antibody (6.3 vs. 44.3%, p=0.005). Subjective xerophthalmia and xerostomia rates were similar between the groups, but fewer non-sicca SS patients had sicca symptoms as chief complaints (18.8 vs. 58.6%, p=0.004). There were no significant differences in focus score, leukocyte and lymphocyte counts, serum IgG levels, and positive rheumatoid factor and antinuclear antibody levels. The maximum European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) score during follow-up showed no significant difference (3.34±4.27 in non-sicca SS vs. 3.83±4.68 in sicca SS, p=0.30). However, more non-sicca SS patients had ESSDAI scores ≧ 1 (100 vs. 71.4%, p=0.015), a positive correlation with the biological domain of the ESSDAI (87.5 vs 58.6%, p=0.03), and articular symptoms (37.5 vs 8.6%, p=0.003).

Conclusions Non-sicca SS patients were younger, had shorter disease duration, and a higher rate of positive correlation with the biological and articular domains of the ESSDAI. Moreover, all non-sicca SS patients had ESSDAI scores ≥1. When we diagnose SS patients without objective sicca symptoms, we should assess age, disease duration, and extraglandular organ involvement before performing labial salivary gland biopsy.

Disclosure of Interest None declared