Surrogate decision making: The challenge of deciding on behalf of others

Various medical conditions can rob people of the ability to participate in decisions about their own treatment. In the United States, for instance, as many as 15,000 patients who live in a persistent vegetative state and another 100,000 who are minimally conscious cannot express their preferences in the event of life-threatening complications. Moreover, the dementia caused by Alzheimer’s disease – of which there are currently 47 million cases worldwide (rising to an estimated 131 million by 2050) – can deprive even fully conscious people of the power to make medical choices, as can severe brain injuries also in younger people (e.g., due to an accident).

Making surrogate decisions on behalf of incapacitated patients can raise difficult questions for relatives, physicians, and society. Previous research has focused on the accuracy of surrogate decisions (i.e., the proportion of correctly inferred preferences). Less attention has been paid to the procedural preferences that patients' surrogates and patients have regarding specific approaches to making surrogate decisions. We therefore assessed potential surrogates' and patients' procedural preferences with different approaches to making surrogate decisions (Studies 1 and 3), as well as the accuracy of potential surrogates in real families (Study 2).

To assess the accuracy of potential surrogates, we randomly assigned a "target person" in each of 64 families, and the remaining family members were asked to infer this target person's treatment preferences in 24 medical scenarios (i.e., whether to resuscitate or not). The figure below shows the accuracy of different approaches to surrogate decision making. We did not assess the accuracy of physicians (*1) and statistical prediction rules (*2), and only preliminary data from other studies exist on these two approaches (the latter estimates may be inflated because relatively easy scenarios have been used). All in all, the various approaches do not seem to achieve substantial differences in accuracy.

Accuracy of different approaches to making a surrogate decision. Data for physicians (*1) and statistical prediction rules (*2) are from other studies, and the latter estimates may be inflated due to the use of relatively easy scenarios.

Given that these differences in accuracy between the currently available approaches to making surrogate decisions are negligible, it is all the more important to have a solid empirical assessment of people’s procedural preferences. The findings of representative population surveys in Germany and Switzerland (see figure below) suggest that procedural preferences for six different approaches vary markedly. Yet the preferences of respondents taking the perspective of incapacitated patients corresponded closely with those of respondents taking the perspective of a potential surrogate.


Procedural preferences of potential surrogates and patients with different approaches to making a surrogate decision, separately for Germany and Switzerland (representative population surveys).

The preferred approaches were a patient-designated surrogate and all family members making a collective decision by means of group discussion. The two least-preferred approaches were relying on a statistical prediction rule and delegating the decision to a physician. Although respondents taking the perspective of an incapacitated patient preferred a patient-designated surrogate, few people have designated such a surrogate in practice. Policy makers may thus consider implementing active choice. Moreover, potential patients and surrogates alike highly valued shared surrogate decisions among family members, suggesting that this possibility should be acknowledged explicitly in future legislation, and caregivers and physicians may consider promoting shared surrogate decisions in practice.


Key references

Frey, R., Hertwig, R., & Herzog, S. M. (2014). Surrogate decision making: Do we have to trade off accuracy and procedural satisfaction? Medical Decision Making, 34, 258-69. doi:10.1177/0272989X12471729

Frey, R., Herzog, S. M., & Hertwig, R. (2018). Deciding on behalf of others: A population survey on procedural preferences for surrogate decision-making. BMJ Open, 8, e022289. doi:10.1136/bmjopen-2018-022289 | PDF

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