Cost-utility analysis of antiviral use under pandemic influenza using a novel approach - linking pharmacology, epidemiology and heath economics.

Simulation models are used widely in pharmacology, epidemiology and health economics (HEs). However, there have been no attempts to incorporate models from these disciplines into a single integrated model. Accordingly, we explored this linkage to evaluate the epidemiological and economic impact of oseltamivir dose optimisation in supporting pandemic influenza planning in the USA. An HE decision analytic model was linked to a pharmacokinetic/pharmacodynamics (PK/PD) - dynamic transmission model simulating the impact of pandemic influenza with low virulence and low transmissibility and, high virulence and high transmissibility. The cost-utility analysis was from the payer and societal perspectives, comparing oseltamivir 75 and 150 mg twice daily (BID) to no treatment over a 1-year time horizon. Model parameters were derived from published studies. Outcomes were measured as cost per quality-adjusted life year (QALY) gained. Sensitivity analyses were performed to examine the integrated model's robustness. Under both pandemic scenarios, compared to no treatment, the use of oseltamivir 75 or 150 mg BID led to a significant reduction of influenza episodes and influenza-related deaths, translating to substantial savings of QALYs. Overall drug costs were offset by the reduction of both direct and indirect costs, making these two interventions cost-saving from both perspectives. The results were sensitive to the proportion of inpatient presentation at the emergency visit and patients' quality of life. Integrating PK/PD-EPI/HE models is achievable. Whilst further refinement of this novel linkage model to more closely mimic the reality is needed, the current study has generated useful insights to support influenza pandemic planning.

Is universal HLA-B*15:02 screening a cost-effective option in an ethnically diverse population? A case study of Malaysia.

BACKGROUND: A strong association has been documented between HLA-B*15:02 and carbamazepine-induced severe cutaneous adverse reactions (SCARs) in Asians. Human leucocyte antigen testing is potentially valuable in many countries to facilitate early recognition of patient susceptibility to SCARs. OBJECTIVES: To determine the cost-effectiveness of universal HLA-B*15:02 screening in preventing carbamazepine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in an ethnically diverse Malaysian population. METHODS: A hybrid model of a decision tree and Markov model was developed to evaluate three strategies for treating newly diagnosed epilepsy among adults: (i) carbamazepine initiation without HLA-B*15:02 screening (current practice); (ii) universal HLA-B*15:02 screening prior to carbamazepine initiation; and (iii) alternative treatment [sodium valproate (VPA)] prescribing without HLA-B*15:02 screening. Base-case analysis and sensitivity analyses were performed over a lifetime time horizon. Incremental cost-effectiveness ratios were calculated. RESULTS: Both universal HLA-B*15:02 screening and VPA prescribing were dominated by current practice. Compared with current practice, universal HLA-B*15:02 screening resulted in a loss of 0·0255 quality-adjusted life years (QALYs) at an additional cost of 707 U.S. dollars (USD); VPA prescribing resulted in a loss of 0·2622 QALYs at an additional cost of USD 4127, owing to estimated differences in antiepileptic treatment efficacy. CONCLUSIONS: Universal HLA-B*15:02 screening is unlikely to be a cost-effective intervention in Malaysia. However, with the emergence of an ethnically diverse population in many other countries, this may render HLA-B*15:02 screening a viable intervention when an increasing proportion of the population is at risk and an equally effective yet safer antiepileptic drug is available.