Probability Discounting and Cardiovascular Risk: The Effect of Side-Effect Severity and Framing
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An expectation of healthcare delivery is that patients can make informed decisions about whether and how to treat chronic health conditions. Decisions are complex because treatment is not always 100% effective and side effects can occur without a beneficial outcome. It is important, therefore, to understand the drivers of individual choices about whether to accept a treatment, particularly, how people respond to the probabilities of being well or unwell with or without the treatment. The current project investigated this using a probability discounting framework. Participants indicated whether they would take a drug that reduced their chance of having a heart attack or a stroke from a baseline probability that varied across trials. We told participants that they would always experience a side effect and manipulated its severity (i.e. either frequent headaches or persistent cold hands and feet). We also manipulated whether probabilities were framed negatively—in terms of heart attack or stroke—or positively—in terms of continued good heart health. We observed systematic discounting as a function of probability of heart attack or stroke without treatment. Discounting was shallower when the side effect was less severe. There was no significant effect of framing at the group level. Overall, probability discounting offers a useful approach to investigating the drivers of decisions about whether to accept medical treatment.
KeywordsProbability discounting Choice decision-making Health Heart attack Stroke Side effects
The authors would like to thank Pharmac New Zealand, and the Victoria University of Wellington Summer Scholarship programme. This data set was presented at the New Zealand Association for Behaviour Analysis conference in 2016.
Compliance with Ethical Standards
This project was funded by a grant from Pharmac New Zealand and a Summer Research Scholarship 2015 – 2016 from Victoria University of Wellington (grants do not have numbers).
Conflict of Interest
Authors 1 and 3 have received the grants from both of the above funders. Neither funder had any input into or oversight of the contents of this manuscript. The authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the Victoria University of Wellington and with the 1964 Helsinki Declaration and its later amendments.
Informed consent was obtained from all individual participants included in the study.
- AFT Pharmaceuticals Ltd. (2009). Cilazapril-AFT. [Data sheet]. Retrieved from http://www.medsafe.govt.nz/profs/datasheet/c/Cilazapril-AFTtab.pdf.
- Akl, E. A., Oxman, A. D., Herrin, J., Vist, G. E., Terrenato, I., Sperati, F., & Schunemann, H. (2011). Framing of health information messages. Cochrane Database of Systematic Reviews, 12, 1–82.Google Scholar
- Barrett, B., Ricco, J., Wallace, M., Kiefer, D., & Rakel, D. (2016). Communicating statin evidence to support shared decision-making. BMC Family Practice, 17(41), 1–9.Google Scholar
- Montgomery, A. A., Harding, J., & Fahey, T. (2001). Shared decision making in hypertension: the impact of patient preferences on treatment choice. Family Practice, 18, 309–313.Google Scholar
- Msaouel, P., Kappos, T., Tasoulis, A., Apostolopoulos, A. P., Lekkas, I., Tripodaki, E., & Keramaris, N. C. (2014). Assessment of cognitive biases and biostatistics knowledge of medical residents: a multicenter, cross-sectional questionnaire study. Medical Education Online, 19, 1–10.CrossRefGoogle Scholar
- Mylan New Zealand Limited. (2013). Cardinol LA [Data sheet]. Retrieved from http://www.medsafe.govt.nz/profs/datasheet/c/Cardinol-LAcap.pdf.
- New Zealand Guidelines Group. (2012). New Zealand Primary Care Handbook 2012 (3rd ed.). Wellington: New Zealand Guidelines Group.Google Scholar
- Pfizer New Zealand Limited. (2015). Zarator [Data sheet]. Retrieved from http://www.medsafe.govt.nz/profs/datasheet/z/ZaratorRoundNewtab.pdf.
- Shepherd, H. L., Barratt, A., Trevena, L. J., McGeechan, K., Carey, K., Epstein, R. M., & Tattersall, M. H. N. (2011). Three questions that patients can ask to improve the quality of information physicians give about treatment options: a cross-over trial. Patient Education and Counselling, 84, 379–385.CrossRefGoogle Scholar
- Weymiller, A. J., Montori, V. M., Jones, L. A., Gafni, A., Guyatt, G. H., Bryant, S. C., Christianson, T. J. H., Mullan, R. J., & Smith, S. A. (2007). Helping patients with type 2 diabetes mellitus make treatment decisions: statin choice randomized trial. Archives of Internal Medicines, 167, 1076–1082.CrossRefGoogle Scholar