Modelling the cost effectiveness of TNF-alpha antagonists in the management of rheumatoid arthritis: results from the British Society for Rheumatology Biologics Registry.
OBJECTIVE
To evaluate the cost effectiveness of TNF-alpha antagonist therapies for rheumatoid arthritis (RA) in the United Kingdom using data from the British Society for Rheumatology Biologics Registry (BSRBR).


METHODS
A simulation model is constructed to quantify the cost effectiveness of the TNF-alpha antagonist therapies (infliximab, etanercept and adalimumab) as a group versus traditional disease-modifying anti-rheumatic drugs, with a time horizon over the full patient lifetime. Participants are UK NHS patients in the BSRBR with RA who have failed at least two traditional disease-modifying anti-rheumatic drugs. The BSRBR aims to recruit all RA patients starting on a TNF-alpha antagonist agent and follows them 6 monthly via consultant and patient administered questionnaires. Data collected include disease activity scores (DAS28), the Health Assessment Questionnaire and the SF-36. Costs include drug, monitoring and hospitalisations. Benefits are measured in disability and quality of life improvements. The main outcome measure is the incremental cost per quality adjusted life-year gained (discounted).


RESULTS
The basecase cost per quality adjusted life-year gained by using TNF-alpha antagonist therapies is estimated at pound23 882, with probabilistic uncertainty analysis suggesting that the probability that treatments are below 30,000 pounds per QALY is around 84%. The results are most sensitive to assumptions concerning long-term disability progression, discount rates and the validity or otherwise of SF6D derived utility measures. Subgroup analysis, monotherapy versus combination with methotrexate, and a limited analysis of sequential therapy with two TNF-alpha antagonist agents, suggest cost-effectiveness ratios around 20,000 pounds to 30,000 pounds.


CONCLUSIONS
The BSRBR data provide valuable evidence for estimating cost-effectiveness. The analysis concludes that current policies and practice for the use of TNF-alpha antagonist therapies, after RA patients have failed at least two traditional disease-modifying anti-rheumatic drugs, appear cost-effective in the context of the NICE re-appraisal of 2006 for England and Wales, thus supporting their decision to continue their reimbursement. Decision-makers worldwide might adapt this analysis because differential costs, discount rates and other factors could affect results. There remains uncertainty, particularly on long-term disease progression. Further data collection using the BSRBR is recommended, together with a revision to this analysis when data become available.
Brennan
A
A
Health Economics and Decision Science, School of Health and Related Research (ScHARR), The University of Sheffield, UK. a.brennan@sheffield.ac.uk
Bansback
N
N
Nixon
R
R
Madan
J
J
Harrison
M
M
Watson
K
K
Symmons
D
D
D000368:Aged; D018501:Antirheumatic Agents / Q000191:economics / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000191:economics*; D003198:Computer Simulation; D003362:Cost-Benefit Analysis; D016527:Drug Costs / Q000706:statistics & numerical data; D004812:Epidemiologic Methods; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data; D006801:Humans; D007155:Immunologic Factors / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017059:Models, Econometric; D019057:Quality-Adjusted Life Years; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D006113:United Kingdom
D018501:Antirheumatic Agents; D007155:Immunologic Factors; D014409:Tumor Necrosis Factor-alpha