To evaluate the association between the degree of involvement shown by parotid scintigraphy at diagnosis and the disease expression, outcomes, and prognosis of primary Sjögren's syndrome (SS).
All patients consecutively diagnosed with primary SS in our department between 1984 and 2008 were evaluated. The scintigraphic stages were classified into class 4 (severe involvement), class 2-3 (mild to moderate involvement), and class 1 (normal results).
A total of 405 patients with primary SS underwent parotid scintigraphy at diagnosis (47 had class 1 involvement, 314 had class 2-3, and 44 had class 4). Patients with class 4 had a higher frequency of parotid enlargement (p < 0.001), systemic involvement (p = 0.007), high titers of antinuclear antibody (p = 0.016), positive rheumatoid factor (p = 0.002), anti-Ro/SSA (p = 0.001), anti-La/SSB (p = 0.001), low C4 levels (p = 0.001), and low CH50 (p = 0.001) in comparison with the other 2 groups. A higher rate of lymphoma development was observed in patients with class 4 involvement. Adjusted multivariate Cox regression analysis showed a hazard ratio (HR) of 10.51 (p = 0.002) and Kaplan-Meier analysis a log-rank of 0.0005. Mortality was 5-fold higher in patients with class 4 involvement. Adjusted multivariate Cox regression analysis showed an HR of 5.33 (p = 0.001) and Kaplan-Meier analysis a log-rank of 0.033.
Patients with SS presenting with severe scintigraphic involvement at diagnosis had a more pronounced autoimmune expression, a higher risk of developing systemic features and lymphoma, and a lower survival rate. Study of the degree of salivary gland dysfunction at diagnosis by parotid scintigraphy offers valuable clinical information on the prognosis and outcome of primary SS.