Several studies have demonstrated that primary Sjögren's syndrome (SS) is associated with reduced productivity; however, the impact of primary SS on daily function is not fully understood. This study aims to assess the physical function of primary SS patients and determine the relationship between the functional impairment experienced by primary SS patients and disease activity, patient-reported symptoms, and quality of life.
Sixty-nine primary SS patients from a specialist clinical service were assessed for their functional ability (Improved Health Assessment Questionnaire [HAQ]), dryness, pain, and overall primary SS-related symptom burden; systemic disease activity; levels of fatigue, daytime somnolence, anxiety, and depression symptoms; quality of life; and systemic inflammation (erythrocyte sedimentation rate, C-reactive protein [CRP] level). Data were compared to 69 healthy volunteers matched for age and sex.
Primary SS patients experienced greater functional impairment than controls (Improved HAQ total scores: mean ± SD 24 ± 25 for primary SS versus 9 ± 19 for controls; P = 0.0002) across all domains of activity. In primary SS, functional impairment was significantly associated with physical fatigue (P < 0.0001, R(2) = 0.3), pain (P < 0.0001, R(2) = 0.3), depression (P < 0.0001, R(2) = 0.3), total symptom burden (P < 0.0001, R(2) = 0.3), systemic disease activity (P = 0.002, R(2) = 0.15), quality of life (P < 0.0001, R(2) = 0.3), dryness (P = 0.002, R(2) = 0.12), daytime somnolence (P = 0.02, R(2) = 0.08), anxiety score (P = 0.03, R(2) = 0.07), and CRP level (P = 0.04, R(2) = 0.06). Only CRP level is independently associated with functional impairment (β = 0.38, P = 0.025).
Primary SS patients experience significant functional disability compared to age-matched healthy controls. Impaired function is associated with reduced quality of life and symptoms such as pain, fatigue, and depression, as well as disease activity, illustrating the importance of optimal management of all aspects of the disease.