Validation of the Sicca Symptoms Inventory for Clinical Studies of Sjögren's Syndrome

Objective: Oral, ocular, and other dryness are the hallmark features of Sjögren's syndrome (SS). We constructed a new measure of sicca symptoms, the Sicca Symptoms Inventory, for the evaluation of patients with primary SS.

Methods: Female Caucasian groups of patients with primary SS, systemic lupus erythematosus, and rheumatoid arthritis and healthy controls were assessed for tear and saliva production and also completed a symptoms-profiling inventory construct-validated from primary SS patients' own vocabulary, augmented with sicca items from publications and participating clinicians. Multi-item facets of sicca and other discomfort were validated by factor analysis.

Results: Primary SS and other "sicca" conditions were highly discriminated from other rheumatic disorders and healthy controls on each dryness-related facet of oral and ocular discomfort. Selected symptom scores were as sensitive and specific to primary SS as the scores for saliva and tears, respectively, although the severity scores of symptoms and signs were only moderately correlated.

Conclusion: These multiple-question scales distinguish patients with primary SS from controls more precisely than previously used measures. Future studies will test if change in these symptom scores can serve as an outcome measure for clinical trials in SS.