Yesterday Dr Jason Guertin presented on the overlap between pharmacoepidemiology and pharmacoeconomics, challenges to translating research into decision making and the potential transition between epidemiology and health economics.
The speaker introduced the incremental cost-effectiveness ratio (ICER), and went on to describe the confounding challenges to determining it. This ratio is the increase/decrease in cost per unit change in effectiveness (e.g. quality of life or years gained unit) for a new drug/technology, compared to its predecessor. The ICER is the key outcome in pharmacoeconomics and cost-effectiveness research for health technologies in general. It is analogous to the usual health outcomes we study in epidemiology. Similar to epidemiology, confounding is a problem in cost-effectiveness research based on observational studies. However, the ICER is actually composed of two things rather then just one health outcome – the cost component and the effectiveness component. Confounding takes on new life because of these two outcomes and the positive or negative correlation between them.
In epidemiology, our effect estimates can swing above and below the null when confounders are excluded or included. In cost-effectiveness research, the cost per quality of life years gained can swing above and below the acceptable threshold to approve new drugs/technologies for reimbursement. In an extreme example, Dr Guertin found a difference of up to $80,000 per quality-adjusted life year gained between unadjusted and adjusted models. Evidently such a price tag has practical implications for decision-making – in this case whether to approve a new technology to treat aortic aneurysm.
Beyond the actual study, translating findings into policy faces further complications. The public reaction has a bigger influence on the technologies and drugs approved then even the best quality cost-effectiveness studies. For example, a very expensive drug to treat rare genetic disorders in infants may be approved because of the value society places on young lives. At the same time, treatments for hair loss are not approved for reimbursement despite their extreme cost-effectiveness. In epidemiology, we face similar challenges. For example, maternity leave allowances of 6 weeks may lead to better breastfeeding outcomes. Say the research on this issue was perfect. Would the policy be implemented everywhere? No.
In sum, Dr Guertin effectively translated his health economics research into a language epidemiologists could understand. The overlap in confounding and study design-related challenges demonstrated that the skills also overlap. So, pharmacoeconomics may be a new field to pursue for you!