Abstract
INTRODUCTION: Primary Sjögren's syndrome (pSS) is a chronic inflammatory condition, which presents with symptoms of dryness, pain, fatigue and often symptoms of anxiety and depression. Health-related quality of life (HRQoL) is significantly reduced in pSS and the direct and indirect health costs of pSS are substantial. This study aims to determine how symptom burden, disease activity and demographics associate with HRQoL longitudinally over a median of 24-month follow-up period in pSS. METHODS: Longitudinal EuroQoL-5 dimension (EQ-5D)-3L data from the Newcastle pSS cohort (n = 377) were evaluated using a survival analysis strategy. Kaplan-Meier and Cox proportional hazards analysis were performed using baseline Newcastle Sjogren's Stratification Tool (NSST) subgroup, EULAR Sjogren's Syndrome Patient Reported Index (ESSPRI), EULAR Sjogren's Syndrome Disease Activity Index (ESSDAI), disease duration, age and sex as covariates including polypharmacy and comorbidity score, where data were available (n = 191). RESULTS: Of the 377 pSS participants analysed in this study, 16% experienced a decline in HRQoL to a health state comparable to or worse than death. NSST subgroup and ESSPRI score had a significant relationship with time to 'EQ-5D event', whereas baseline ESSDAI, age, disease duration and sex did not. CONCLUSION: In pSS, symptom burden and to a great extent NSST subgroup, rather than systemic disease activity, has a significant relationship with HRQoL longitudinally. Improvements in symptom burden have the potential to produce significant impacts on long-term HRQoL in pSS.