• actigraphy
• chronotype
• circadian rhythm
• dryness
• fatigue
• rheumatology
• Sjögren
• Sjögren's disease
• sleep

Background: Sjögren’s Disease (SjD) is a systemic autoimmune disorder that primarily affects the exocrine glands, leading to dryness of the mouth and eyes (sicca symptoms). In addition to these symptoms, SjD can lead to severe systemic manifestations, including arthritis, lung disease, vasculitis, and an increased risk of developing B-cell non-Hodgkin’s lymphoma. Many patients report debilitating fatigue, pain, and dryness, which significantly diminish quality of life. While sleep disturbances in SjD are recognized, few studies have objectively assessed sleep through wrist actigraphy, and none have comprehensively explored circadian rhythm alterations or their clinical relevance.

Objective: This study aimed to: (1) compare subjective and actigraphy-derived sleep and circadian parameters in SjD patients versus healthy controls (HCs); and (2) investigate how these measures relate to disease activity and patient-reported outcomes.

Methods: In a cross-sectional design, female SjD patients meeting the 2016 ACR/EULAR criteria and matched HCs (by age, sex, and BMI) were enrolled. All participants wore wrist actigraphs for seven days. Subjective assessments included the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and the reduced Morningness-Eveningness Questionnaire (rMEQ). Circadian parameters were analyzed using both parametric and non-parametric methods. Patient-reported outcomes included the ESSPRI, FACIT, and HADS, while disease activity was measured via the ESSDAI.

Results: A total of 46 SjD patients and 40 HCs were included in the study. Compared to HCs, SjD patients showed significantly poorer subjective sleep quality and increased daytime sleepiness. Actigraphy revealed decreased sleep efficiency, greater wake after sleep onset (WASO), and an earlier sleep midpoint and advanced acrophase, suggesting a circadian shift towards eveningness. Worse subjective sleep quality and lower sleep efficiency were associated with higher symptoms burden (ESSPRI) and mood disorders (HADS). Sensitivity analyses indicated that increased disease activity (ESSDAI) was related to longer sleep duration, less sleep regularity and reduced daytime activity (fewer steps).

Conclusion: Sleep and circadian rhythm disturbances in SjD are evident at both subjective and objective levels. These alterations show strong associations with disease severity, affective symptoms, and reduced physical activity levels. Circadian dysregulation may represent a previously overlooked aspect of SjD, with potential implications for therapeutic interventions.