EuroQol-5 dimensions utility gain according to British and Swedish preference sets in rheumatoid arthritis treated with abatacept, rituximab, tocilizumab, or tumour necrosis factor inhibitors: a prospective cohort study from southern Sweden

BACKGROUND: The development of EuroQol-5 dimensions (EQ-5D) utility over time in rheumatoid arthritis (RA) patients, treated with biologics other than tumour necrosis factor inhibitors (TNFi), based on the standard British (UK) and the new Swedish (SE) EQ-5D preference sets, has not been previously described. METHODS: Demographics, core set data, EQ-5D utility, and treatment characteristics for patients with established RA, receiving biologics in southern Sweden from January 2006 to March 2014, were retrieved from observational databases. Theoretical, UK, and experience-based, SE, EQ-5D mean utilities were plotted over time. RESULTS: Data regarding 2418 treatment courses with abatacept (ABA, n = 100), rituximab (RTX, n = 230), tocilizumab (TOC, n = 121), or TNFi (n = 1967) were included in the analysis. Patients starting TNFi treatment, as expected, had shorter disease duration and less previous biologics. Baseline utilities of patients commencing ABA and TOC, but not RTX, were also lower than in the TNFi group. Following treatment initiation, rapid utility improvements were seen with all therapies, reaching plateaus after approximately 1.5 months, and then remaining fairly stable throughout follow-up in patients adhering to therapy. SE utilities were consistently higher than UK, with baseline values at around 0.7 leaving little room for improvement. CONCLUSIONS: ABA, RTX, TOC, and TNFi treatments were all associated with favourable EQ-5D utility developments in RA patients adhering to therapy. The compression of the experience-based SE preference set towards higher utilities may compromise its ability to detect between-group differences in quality-adjusted life-years, thus making cost-effectiveness harder to demonstrate in cost-utility analyses applying this preference set, rather than the standard UK.