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Psoriatic Arthritis: Creating a Model for Cost-Effectiveness Analysis. GRAPPA meeting San Antonio, TX October 15, 2004 Supported by Schering Participants: D. Gladman, P. Mease, C. Antoni, A. Kavanaugh, V. Farewell, A. Maetzel, C. Marra, J. Wong, J. Pew. Introduction.
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Psoriatic Arthritis:Creating a Model for Cost-Effectiveness Analysis GRAPPA meeting San Antonio, TX October 15, 2004 Supported by Schering Participants: D. Gladman, P. Mease, C. Antoni, A. Kavanaugh, V. Farewell, A. Maetzel, C. Marra, J. Wong, J. Pew
Introduction • Anti-TNF’s provide substantial clinical benefit for patients with psoriatic arthritis but are relatively expensive • National Institutes for Clinical Effectiveness (UK) request: • Cost-effectiveness of etanercept and infliximab for patients with inadequate response to standard DMARD therapy
What are the Requirements to Determine Cost-effectiveness? • Impact of intervention on natural history and costs • IMPACT I • Supplemented by Toronto Psoriatic Arthritis Research Program • Natural history of the disease • Mortality: Toronto Psoriatic Arthritis Research Program • Morbidity or quality of life: EQ-5D in Toronto PsA Program patients • Lifetime cost: • Utilization and drug costs in Toronto Cohort
Cost-Effectiveness Ratio Compares a specific (new) intervention to a stated alternative (old) intervention (Costnew – Costold )/ (Benefitnew – Benefitold ) Incremental resources required by the intervention Incremental health effects gained by using the intervention
Cycle 1 Well Sick Dead Well 2 3 Dead Sick Well Markov Cohort Simulation Model
Attributes Used to Define Markov States • Determine health states by ability to predict death, disability or functional status or costs • Determine likelihood of moving from one health state to the others for each treatment (transition probabilities) in a period of time • Associate with each health state, chance for 1) death, 2) change in health status, 3) quality of life, 4) costs
Potential Heath States for PsA • HAQ categories • May not capture full disease burden • Values lower than for RA • Active joints • 0, 1-4, 5-9, 10+ • Deformed joints • 0, 1-4, 5-9, 10+
Choosing Heath States for PsA • Active joint model • Good gradient with EQ-5D for health related quality of life (poorer QOL with more active joints) • Good gradient for cost (higher costs with more active joints) • IMPACT I patients easily mapped onto health states • Deformed joint model • Gradient for QOL not as good • Gradient for costs better • Mapping of IMPACT I patients problematic
Issues • Patients from IMPACT I appear to have a poorer prognosis than those from the Canadian database • For some patients, we had to use the Toronto database to estimate prognosis (underestimate disease progression) • PASI only has mild EQ-5D impact
Economic Project and GRAPPA • What should the role of GRAPPA be? • Endorsement of work already done • Level of involvement • Other companies doing similar assessments