Beyond sicca: high prevalence and predictors of baseline and worsening systemic involvement in patients with Sjögren's disease

Objectives Systemic extraglandular involvement in SS has been reported in one-third of patients but may be more frequent. We aimed to evaluate systemic disease prevalence at baseline and throughout follow-up and find its predictors.Methods We conducted a retrospective cohort study including SS patients followed in a tertiary centre. The cumulative EULAR SS disease activity index (ESSDAI) was calculated by adding each domain's maximum score throughout follow-up. We identified independent predictors of systemic involvement (ESSDAI >= 1 at baseline and/or follow-up) through logistic regression modelling. A survival analysis was conducted to identify predictors of new/worsening ESSDAI domains.Results A total of 216 patients were included, most of whom had systemic involvement (86%), frequently at diagnosis (76%). Biological (53%) and articular ESSDAI domains (44%) were most commonly involved, but all were affected at least once. Around half of the patients with baseline systemic disease developed an additional/worsening domain throughout follow-up. Although most patients had low disease activity at baseline, 60% eventually reached moderately active disease. Younger age at diagnosis [odds ratio (OR) 0.95 (95% CI 0.91, 0.99)], a positive minor salivary gland biopsy [OR 4.08 (95% CI 1.40, 11.86)] and RF [OR 4.67 (95% CI 1.52, 14.33)] were independent predictors of systemic involvement. Patients with baseline constitutional involvement [hazard ratio (HR) 2.23 (95% CI 1.13, 4.40)] and RF [HR 1.89 (95% CI 1.20, 3.00)] were more likely to develop new/worsening systemic disease activity.Conclusion Systemic involvement is seen in most SS patients. Younger and RF and salivary gland biopsy-positive patients are at higher risk of systemic disease. Around half of patients with systemic involvement experienced aggravated disease over time, especially those with constitutional involvement or RF. What does this mean for patients?Sjogren's syndrome (SS) is a rheumatic disease known for its characteristic symptoms of dry eyes and mouth, chronic pain and fatigue. While primarily affecting the glands, SS can also affect other organs, referred to as systemic involvement. Systemic involvement in SS has traditionally been reported in one-third of patients, but recent research suggests it may be more common. Our objective was to evaluate how common systemic involvement is in SS at diagnosis and throughout follow-up and identify characteristics that may be associated with its occurrence. We looked at medical records of 216 SS patients and found that most of them (86%) had systemic involvement at some point during their follow-up. The most commonly affected areas were the blood (53%) and joints (44%). We discovered that younger patients and those with positive rheumatoid factor and salivary gland biopsy were more likely to have systemic involvement. Also, those with general symptoms (fever, weight loss, night sweats) or rheumatoid factor were at an increased risk of worsening of the disease. This study characterizes how systemic involvement varies throughout the disease course, a novel insight on the natural history of SS. The uncovered risk factors can help identify patients who may need closer monitoring. By recognizing these factors associated with systemic involvement, healthcare professionals can provide better care and improve outcomes for SS patients.