Incorporating Future Medical Costs: Impact on Cost-Effectiveness Analysis in Cancer Patients.
Tew M., Clarke P., Thursky K., Dalziel K.
BACKGROUND: The inclusion of future medical costs in cost-effectiveness analyses remains a controversial issue. The impact of capturing future medical costs is likely to be particularly important in patients with cancer where costly lifelong medical care is necessary. The lack of clear, definitive pharmacoeconomic guidelines can limit comparability and has implications for decision making. OBJECTIVE: The aim of this study was to demonstrate the impact of incorporating future medical costs through an applied example using original data from a clinical study evaluating the cost effectiveness of a sepsis intervention in cancer patients. METHODS: A decision analytic model was used to capture quality-adjusted life-years (QALYs) and lifetime costs of cancer patients from an Australian healthcare system perspective over a lifetime horizon. The evaluation considered three scenarios: (1) intervention-related costs (no future medical cost), (2) lifetime cancer costs and (3) all future healthcare costs. Inputs to the model included patient-level data from the clinical study, relative risk of death due to sepsis, cancer mortality and future medical costs sourced from published literature. All costs are expressed in 2017 Australian dollars and discounted at 5%. To further assess the impact of future costs on cancer heterogeneity, variation in survival and lifetime costs between cancer types and the implications for cost-effectiveness analysis were explored. RESULTS: The inclusion of future medical costs increased incremental cost-effectiveness ratios (ICERs) resulting in a shift from the intervention being a dominant strategy (cheaper and more effective) to an ICER of $7526/QALY. Across different cancer types, longer life expectancies did not necessarily result in greater lifetime healthcare costs. Incremental costs differed across cancers depending on the respective costs of managing cancer and survivorship, thus resulting in variations in ICERs. CONCLUSIONS: There is scope for including costs beyond intervention costs in economic evaluations. The inclusion of future medical costs can result in markedly different cost-effectiveness results, leading to higher ICERs in a cancer population, with possible implications for funding decisions.