OBJECTIVES: Decisions about the use of new medical technologies based on estimates of the average cost-effectiveness across a potentially heterogeneous population runs the risk of foregoing net health benefits(NHB) for sub-groups of the population. We propose a general framework within which to assess betweenpatient heterogeneity and its role in cost-effectiveness subgroup analysis(CESA), complementing this with a practical application. METHODS: We first describe how to extend methods for cost-effectiveness analysis (based on current information) to address issues such as estimation of NHB, sources of heterogeneity, definition and selection of subgroups. Next, we define the role of uncertainty in CESA, extending the concept of Value of Information(VoI) to include the notion of a static and dynamic Value of Heterogeneity(VoH). The application of the proposed theoretical framework is illustrated using a cost-effectiveness model developed for the analysis of a multicentre-trial(RITA-3), which assessed the efficacy of an early arteriography with revascularisation versus standard management in patients with acute coronary-syndrome. Using this model we conducted a re-analysis investigating alternative subgroup specifications, varying between one and five subgroups, with a view to produce an efficiency frontier for subgroup analysis relating to this decision problem. We assessed the static and dynamic VoH under each specification. RESULTS: The population expected NHB when considering five subgroups was 105,500 QALYs greater than decision based on estimates for the average population (static-VoH). Although, identifying 5 subgroups reduced in the Expected Value of Perfect Information(EVPI) (920 QALYs, at a threshold of £30,000/QALY), the potential NHB from resolving uncertainty was greater after heterogeneity has been identified (dynamic-VoH). CONCLUSIONS: Our initial findings support the argument that explicit consideration of heterogeneity in CEA leads to a positive static and dynamic VoH. In addition, heterogeneity not only may increase the EVPI but can also reduce its magnitude. The VoH framework offers a useful guidance for a more systematic CESA.

OBJECTIVES: to explore the effects of patient self-testing (PST) of oral anticoagulation therapy (OAT) by CoaguChek ® XS System compared to standard available care (laboratory testing) for selected group of patients. METHODS: Health Economy Model (HECON), using Cost-Effectiveness Analysis (CEA), complemented by Budget-Impact Analysis (BIA) on public health insurance coverage in Slovakia. We searched MEDLINE, Cochrane and available grey literature (Industrial Sources and Expert Opinions) for meta analyses, systematic reviews, economic evaluation studies and health technology reports on PST of OAT. Outcomes analyzed were feasibility and accuracy of PST, thromboembolic events, hemorrhagic complications and mortality. Real-world data from General Health Insurance, Inc. were used for costs associated with corresponding diagnoses, complications and management of patients on OAT, including full cohort of patients (nϭ100, average age of 63 years) on PST. Markov Model (life time horizon) for OAT patient management was developed, comparing PST with standard care. Outcomes observed were major thromboembolic events, major hemorrhagic complications and mortality. Payer perspective and direct healthcare costs only, associated with OAT management were considered in CEA and BIA for diagnosis subgroups. Discount rate of 5% was used for costs as well as outcomes. Sensitivity analysis for major complications was performed. RESULTS: CEA for PST vs. standard care associated with OAT shows that intervention is cost-effective (dominant) for all diagnosis subgroups. Net costs (BIA) associated with PST for expanding the existing cohort of patients 10 times (nϭ1000) are 1.596 mil. € in Year 1 (up to 3.579 € in Year 5). CONCLUSIONS: PST of OAT is considered cost-effective in terms of International Normalized Ratio (INR) regulation and safer in terms of complications. Moreover, analysis of selected subpopulations (mitral and/or aortic mechanical heart valve implantation, aortic and/or other aneurysm and congenital cardiovascular malformations) shows that PST brings the most significant cost-savings especially for those OAT patient segments.

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