Health-related utility values of patients with primary Sjögren's syndrome and its predictors

Abstract

Objectives: EuroQoL-5 dimension (EQ-5D) is a standardised preference-based tool for measurement of health-related quality of life and EQ-5D utility values can be converted to quality-adjusted life years (QALYs) to aid cost-utility analysis. This study aimed to evaluate the EQ-5D utility values of 639 patients with primary Sjögren's syndrome (PSS) in the UK.

Methods: Prospective data collected using a standardised pro forma were compared with UK normative data. Relationships between utility values and the clinical and laboratory features of PSS were explored.

Results: The proportion of patients with PSS reporting any problem in mobility, self-care, usual activities, pain/discomfort and anxiety/depression were 42.2%, 16.7%, 56.6%, 80.6% and 49.4%, respectively, compared with 5.4%, 1.6%, 7.9%, 30.2% and 15.7% for the UK general population. The median EQ-5D utility value was 0.691 (IQR 0.587-0.796, range -0.239 to 1.000) with a bimodal distribution. Bivariate correlation analysis revealed significant correlations between EQ-5D utility values and many clinical features of PSS, but most strongly with pain, depression and fatigue (R values>0.5). After adjusting for age and sex differences, multiple regression analysis identified pain and depression as the two most important predictors of EQ-5D utility values, accounting for 48% of the variability. Anxiety, fatigue and body mass index were other statistically significant predictors, but they accounted for <5% in variability.

Conclusions: This is the first report on the EQ-5D utility values of patients with PSS. These patients have significantly impaired utility values compared with the UK general population. EQ-5D utility values are significantly related to pain and depression scores in PSS.

Keywords: Epidemiology; Qualitative research; Sjagren's Syndrome.