Utility and direct costs: ankylosing spondylitis compared with rheumatoid arthritis

Objectives: To compare utility and disease-specific direct costs between patients with ankylosing spondylitis (AS) and patients with rheumatoid arthritis (RA) in the Netherlands. Methods: Patients with AS and those with RA completed questions on disease characteristics, the EuroQol-5D (EQ-5D) to assess utility, and questionnaire resource utilisation. Resource utilisation was assessed prospectively in AS, but retrospectively in RA. True cost estimates (2003) were used to calculate the costs. Differences in disease characteristics between AS and RA were described, and determinants of EQ-5D utility and costs were explored by Cox proportional hazard regressions. Results: 576 patients with RA and 132 with AS completed the questionnaires. EQ-5D utility (0.63 vs 0.7) was lower, and annual direct costs higher in RA (J5167 vs J2574). In multivariate Cox proportional hazard regressions, there was no difference in utility between the diagnostic groups, but patients with RA incurred higher direct costs after controlling for age, gender and disease duration. Conclusions: In patients with RA and patients with AS, who are under the care of a rheumatologist, utility is equally reduced, but healthcare costs are higher in RA after controlling for age, gender and disease duration. These data can be helpful to provide insights into the differences and similarities between the healthcare needs of both patient groups and to identify issues for further research and for policy in healthcare organisations.