Exocrine function in primary Sjogren syndrome: natural course and prognostic factors

Objectives: Few studies have addressed the natural course of, or prognostic factors for the salivary and lacrimal function in primary Sjogren syndrome (SS). Except for the early stages, glandular function has been seemingly stable, and SS A antigen (SSA) seropositivity and hypocomplementemia may predict a decline in the van Bijsterveld score. The aim of the present study was to assess the natural course of the exocrine function in a larger cohort based on the American-European consensus criteria for SS, and to address possible predictive factors for a declining exocrine function. Methods: We performed a retrospective cohort study. A total of 141 patients were investigated with the Schirmer I test and unstimulated whole saliva (UWS). Historical data regarding these tests and focus score were collected from the files of 111 patients. Median time from diagnosis to follow-up investigation was 5.0 years. Results: Median UWS was unchanged during follow-up. Median Schirmer I test improved from 5.0 to 7.0 mm/5 min (p< 0.05). Present Schirmer I test was associated with historical high IgG and IgA, positive SSA and SS B antigen (SSB) tests and high focus score, and present UWS with historical low C3/C4. Logistic regression identified high focus scores (odds ratio (OR)= 1.343), and low UWS (OR= 0.692) as factors predicting a 30% or more worsening of the Schirmer I test. High focus scores (OR= 1.488) predicted a 30% or more worsening of the UWS. Conclusion: We confirmed previous studies showing a stable or slightly improved exocrine function over time. High focus scores and low UWS were identified as independent predictors of a worsened exocrine function.