Summary:

Doctors and patients can choose how they use subsidised treatments in practice but these choices may have important implications for both healthcare costs and health outcomes. A study comparing healthcare use for patients before and after the funding decision using a newly developed method found that behaviours of both doctors and patients changed. Policy makers should consider these behavioural responses when deciding to fund new treatments but often there is limited information to guide them.

Authors: Peter Ghijben1, Dennis Petrie1, Silva Zavarsek2, Gang Chen1, Emily Lancsar3

  1. Centre for Health Economics, Monash Business School, Monash University, Caulfield East, VIC, Australia
  2. Deakin Health Economics, Institute for Health Transformation, Deakin University, Geelong, VIC, Australia
  3. Department of Health Services Research and Policy, College of Health and Medicine, Australian National University, Canberra, ACT, Australia

In the absence of strong constraints, doctors can decide whom to treat, when to start and stop, how frequently to monitor outcomes, and the use of other therapies (including prior, concurrent and subsequent treatments). Patients can also decide whether or not to follow medical advice and use treatments as prescribed.

Clinical trials intentionally restrict these sorts of behaviours to help determine the direct relationship between health outcomes and treatments free of other behavioural responses. Clinical trials also simply cannot measure how funding a new treatment will cause changes to prior treatments and rarely provide information on subsequent treatments owing to short follow-ups. Real-world studies or pragmatic trials are needed to better understand how doctors and patients are likely to use new treatments in practice and guide policy makers on how to ensure the efficient use of scarce healthcare resources. Our research first considers the incentives that may drive behaviours in practice and then evaluates using real world data how the funding of new prostate cancer treatments in Australia affected healthcare behaviours and what this meant for their value for money.

In the early 2010s, many countries approved subsidised access to three life-extending treatments for meta-static prostate cancer based on efficacy reported in three clinical trials. These treatments included two hormonal drugs (abiraterone and enzalutamide) and a chemotherapy (cabazitaxel), for use after the established first-line treatment (docetaxel). The trials excluded relatively unwell patients and enforced strict stopping criteria, but doctors and patients had more flexibility in deciding how to use the treatments in practice and their incentives meant that we expected their behaviour to differ.

To estimate how the funding of prostate treatments actually affected different types of behaviours, we compare healthcare use for patients before and after the funding decision using a newly developed method. Compared to the trial evidence, doctors treated older and sicker patients with the new treatments and continued them for longer than expected. The availability of the new treatments meant that patients stopped prior treatment earlier and delayed palliative treatments. Doctors also changed how they monitored patients. Once behavioural responses were considered, the cost implications were greater and the estimated health gains were less, which meant the value for money of the new treatments significantly decreased.

Overall, we find behavioural responses not considered by policy makers can have large impacts on the value of money for new treatments. Understanding these behaviours is critical for deciding what to fund or what restrictions, guidelines or education might be needed if funded. More attention should be given to estimating the full cost implications of decisions.

For more information contact: peter.ghijben@monash.edu

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