To design an economic model describing the costs and outcomes for patients treated with tumour necrosis factor alpha (TNFalpha) inhibitors for rheumatoid arthritis (RA) in current clinical practice in Sweden, to be used as a tool to estimate cost-effectiveness of the next generation of treatments.
The model was constructed as a discrete event simulation (DES) model analysed at patient level. It contains treatment and outcome data for 1903 patients followed in the RA registry for biological drugs in southern Sweden between 1999 and 2007 [the Southern Swedish Arthritis Treatment Group (SSATG) Register]. Resource consumption was based on a survey of 1027 patients in the same region. Costs and quality-adjusted life years (QALYs) are presented for 10(5) years, for patients with the mean characteristics at treatment start in SSATG [Health Assessment Questionnaire (HAQ) score 1.33, disease duration 12.1 years, age 55 years], but also for patients with more or less severe disease. Cost and outcomes (QALYs) are discounted with 3%.
The 10-year costs in the base case amount to USD 336,000 (SD USD 64,000) or EUR 223 000, with a total of 4.4 QALYs. Over 5 years, the costs amount to USD 208,000 or EUR 138,000 and QALYs to 2.5. The results were most sensitive to HAQ level at treatment start, but also to underlying disease progression, age, and disease duration. Starting treatment at a lower HAQ level (0.85) reduces costs by 10% and increase QALYs by 20%.
This analysis is based on the longest available follow-up for patients treated with TNFalpha inhibitors and provides an opportunity to explore treatment strategies when new therapies become available using actual clinical practice data.