==== Front BMJ OpenBMJ OpenbmjopenbmjopenBMJ Open2044-6055BMJ Publishing Group BMA House, Tavistock Square, London, WC1H 9JR bmjopen-2018-02228910.1136/bmjopen-2018-022289Evidence Based PracticeResearch150616941326Deciding on behalf of others: a population survey on procedural preferences for surrogate decision-making http://orcid.org/0000-0002-3190-3523Frey Renato 12Herzog Stefan M 2Hertwig Ralph 2 1 Center for Cognitive and Decision Sciences, Department of Psychology, University of Basel, Basel, Switzerland 2 Center for Adaptive Rationality, Max Planck Institute for Human Development, Berlin, Germany Correspondence to Dr Renato Frey; renato.frey@unibas.ch2018 25 7 2018 8 7 e02228913 2 2018 19 4 2018 07 6 2018 © Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.2018This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.Objectives To assess people’s procedural preferences for making medical surrogate decisions, from the perspectives of both a potential surrogate and an incapacitated patient. Design Computer-assisted telephone interviews. Respondents were randomly assigned either the role of an incapacitated patient or that of a potential surrogate for an incapacitated family member. They were asked to rate six approaches to making a surrogate decision: patient-designated surrogate, discussion among family members, majority vote of family members’ individual judgements, legally assigned surrogate, population-based treatment indicator and delegating the decision to a physician. Setting Germany and German-speaking and French-speaking parts of Switzerland. Participants 2010 respondents were quota sampled from a panel (representative for the German and German-speaking and French-speaking Swiss populations, respectively, in terms of age, sex and regions). Main outcome measures Endorsement of each approach (rated on a scale from 1 to 10). Degree to which preferences overlap between the perspective of potential surrogates and potential patients. Results Respondents’ endorsement of the six different approaches varied markedly (from Mdn=9.3 to Mdn=2.6). Yet the preferences of respondents taking the perspective of incapacitated patients corresponded closely with those of respondents taking the perspective of a potential surrogate (absolute differences ranging from 0.1 to 1.3). The preferred approaches were a patient-designated surrogate (Mdn=9.3) and all family members making a collective decision by means of group discussion (Mdn=9.3). The two least-preferred approaches were relying on a statistical prediction rule (Mdn=3.0) and delegating the decision to a physician (Mdn=2.6). Conclusions 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, that is, identifying institutional settings in which many people can be reached (eg, when obtaining a driver’s licence) and requesting them to complete advance directives and to designate a specific surrogate. Moreover, potential patients and surrogates alike highly valued shared surrogate decisions among family members. Policy-makers may consider acknowledging this possibility explicitly in future legislation, and caregivers and physicians may consider promoting shared surrogate decisions in practice. substituted judgementprocedural preferencespopulation surveyadvance directivesliving willspecial-featureunlocked ==== Body Strengths and limitations of this study Past research has focused on the accuracy of different approaches to making surrogate decisions for incapacitated patients, that is, on the proportion of surrogate decisions that are in line with hypothetical patients’ real preferences. These analyses did not find evidence for substantial differences in accuracy between approaches. People’s procedural preferences may therefore be an additional important criterion for evaluating surrogate decision-making approaches, but evidence from representative surveys is currently lacking. This is the first study to report representative evidence on potential patients’ and surrogates’ endorsements of six different approaches to surrogate decision-making. Future research should also assess procedural preferences for combinations of different approaches, which the current study did not do. Introduction Surrogate decisions in the medical context refer to decisions made on behalf of patients who are no longer able to express whether and how they want to be treated, nor specified their treatment preferences in any advance directives. Unfortunately, patients who may depend on a surrogate are no rare exception; for example, in the USA alone 15 000 patients live in a persistent vegetative state and another 100 000 are minimally conscious.1 As only a fraction of the population has completed advance directives regarding their preferred medical treatment (about 10% in non-clinical populations),2 3 for many of these patients a surrogate will have to make medical decisions on their behalf—be it a decision on standard procedures, or a momentous end-of-life decision. Similarly, of the 47 million people worldwide who live with dementia (eg, Alzheimer’s disease), rising to an estimated 131 million by 2050,4 many will eventually lose their ability to make autonomous decisions and depend on a surrogate. The legislation in some countries including several US states (as well as Switzerland and Germany, the setting of the present study)5 6 explicitly permits a person to be designated as surrogate, making a ‘substituted judgement’ in case of necessity with the goal of approximating the patient’s preferences as closely as possible. If no surrogate has been designated by the patient, a default surrogate may be assigned by law, using a nearest-relative hierarchy that starts with the spouse and progresses to one of the patient’s adult children, a parent or an adult sibling. This hierarchy is implemented in the Swiss and other countries’ legislations (but not in effect in Germany).7–9 In the UK, the Mental Health Act stipulates the use of the same hierarchy for mentally incapacitated patients. Other approaches are not anchored in law but may nevertheless be adopted in practice. For example, the patient’s family members may make a joint decision or delegate the decision to a physician. Further approaches, such as relying on a statistical prediction rule (ie, a ‘population-based treatment indicator’), have been suggested in the literature9 but not yet implemented in practice. People who engage in advance care planning, as well as relatives of an incapacitated patient, may therefore be confronted with the question of which approach is best for making a surrogate decision. The different approaches can be evaluated on at least two criteria: accuracy and procedural preference. Accuracy refers to the proportion of surrogate decisions that are in line with incapacitated patients’ true preferences. As the latter by definition cannot be assessed once a patient is incapacitated, the accuracy of surrogate decisions is typically estimated using hypothetical scenarios. A systematic review of studies using such scenarios revealed accuracy levels of 69% for patient-designated surrogates and 68% for legally assigned surrogates.10 More recently, Frey et al 11 found similar levels of accuracy in the context of actual families (n=64), namely 68% for patient-designated surrogates and 70% for surrogates selected according to the nearest-relative hierarchy. In addition, Frey et al assessed the accuracy of different surrogate decisions rendered jointly by family members: Decisions made after open discussion among family members had an accuracy level of 70%, those made after casting individual votes and applying a majority rule had an accuracy level of 71%. Finally, another study found that a preliminary population-based treatment indicator accurately predicted preferences in 78.5% of cases, whereas individual surrogates achieved an accuracy level of 78.4% (note that the authors of this study raised the possibility that the observed accuracy levels may be inflated as a result of the relatively ‘easy’ scenarios used).9 In sum, the predictive accuracies of the various approaches to surrogate decision-making tested to date clearly exceed chance level (which would be 50%, as the scenarios typically require a binary decision) but do not appear to differ appreciably among each other.9 11 The second criterion on which surrogate decisions can be evaluated—procedural preference—refers to potential patients’ and surrogates’ preferences for how a surrogate decision is made—and in particular, by whom. For example, incapacitated patients may wish to delegate their autonomy to the person they feel closest to and trust most. Also potential surrogates may care about how a decision is made; as there will always be some uncertainty, surrogates may struggle with whether they are making the right decision, ponder its acceptance among other family members and possibly anticipate postdecisional regret. They may therefore prefer to make a shared surrogate decision with other family members. As in the canonical definition of ‘shared decision-making’ between a physician and a patient,12 13 sharing could ease the emotional distress potentially experienced by the person who has to make a momentous decision (ie, an individual surrogate). Moreover, shared decisions about important matters lead to an increase in perceived procedural justice, as opposed to those made by an individual alone.14 In line with these concerns, having ‘support and others to talk to’ and ‘working towards consensus’ have been identified as key factors that help surrogates to make these difficult decisions.15 In one study, 18% of actual patient-designated surrogates indicated that they planned to seek input from others in the surrogate’s network.16 Moreover, first evidence from families indicates that both potential patients and surrogates prefer shared decision-making approaches to delegating the decision to a surrogate assigned by a legal hierarchy (even though this person is often the same person the patient would have designated) or to a physician, or to applying a statistical prediction rule.11 Finally, a recent study investigated whether a ‘patient preference predictor’ (PPP, ie, a statistical prediction rule that predicts which treatment a patient would want, based on the treatment that patients in similar circumstances would prefer) was perceived as a valuable and acceptable tool to assist shared decision-making.17 When the PPP was framed as an intervention that would reduce stress on their ‘durable power of attorney’ (typically a family member), 48% of respondents wished the PPP prediction to be considered; when it was presented as an intervention that would increase the chances of being treated consistently with their own preferences, 55% of respondents wished it to be considered. The latter assumption (ie, that a PPP increases predictive accuracy) is not yet supported by empirical evidence, however, and because the framing of the questions in the study may have implied so, this level of agreement could be inflated. Nevertheless, it indicates that a sizeable proportion of people may appreciate the use of some form of a technical decision aid, such as a statistical prediction rule. If the different approaches were to substantially differ in terms of their accuracy, those differences might, of course, influence procedural preferences. However, given that the differences between the currently available approaches to making surrogate decisions are negligible,9–11 it is all the more important to have a solid empirical assessment of people’s procedural preferences. To date, representative assessments of those preferences are lacking. As such, it also remains unknown to what extent potential patients’ and surrogates’ preferences overlap or conflict with each other. Relatedly, it remains unknown to what extent preferences vary as a function of sociodemographic and other relevant characteristics (eg, age, whether a person has prepared a living will or designated a surrogate). Answers to these questions will help to advise people on how best to make surrogate decisions, and as they may have implications for legislation they could thus inform future policy-making. Methods Representative survey We conducted computer-assisted telephone interviews with people aged at least 14 years who lived in Germany (n=1007) or Switzerland (German-speaking and French-speaking parts; n=1003). Respondents were recruited in September 2012 from a panel maintained by an international market research company (Gesellschaft für Konsumforschung) and interviewed in the context of a typical omnibus survey (Telebus); the sizes of the quota-driven samples were chosen such that they are representative for age, sex and regions of the respective populations. The French version of the questionnaire was professionally translated by the survey company, which also conducted the interviews, compensated respondents and provided us with respondents’ sociodemographic information. In the survey, respondents were randomly assigned either the role of an incapacitated patient or the role of an incapacitated patient’s close relative. The interviewers read the instructions for the two perspectives as follows (English translation). Please imagine that you have [a member of your family has] advanced Alzheimer’s disease or are [is] in a coma after an accident. That is, you are [this family member is] no longer capable of making decisions regarding life-sustaining medical treatments. If you [your family member] had not completed a living will with clear instructions, who should make the decisions that may determine your [the family member’s] life and death? I am now going to list six different possibilities. Please tell me how strongly you agree or disagree with each of them. If you [your family member] were incapacitated, how strongly would you want a treatment decision to be made by… Respondents then indicated their preferences on a scale from 1 (strong disagreement) to 10 (strong agreement) for each of the following six possibilities (presented in randomised order for each respondent): A decision should be made (1) by an individual person whom you have (the family member has) previously designated as surrogate; (2) by an individual person determined according to a legal hierarchy (starting with the spouse, followed by an adult child, a parent or an adult sibling); (3) by family members making a collective decision through discussion with the aim of finding a consensus; (4) by family members making a collective decision by casting individual votes and implementing the majority choice; (5) by a physician and (6) in accordance with the decision that the majority of patients in a similar situation would have made. Finally, respondents were asked whether they had completed a living will, designated a potential surrogate and registered as an organ donor. In Germany and Switzerland, active consent is required to become an organ donor (eg, by completing a form downloaded from the internet). Patient and public involvement No patients were involved in setting the research question or the outcome measures, nor were they involved in developing plans for design or implementation of the study. No patients were asked to advise on interpretation or writing up of results. There are no plans to disseminate the results of the research to study participants. Statistical analyses All of the analyses were conducted using R.18 The full dataset is available at http://osf.io/5aa4b. We report respondents’ sociodemographic characteristics (sex, age, household size, employment status, education, income and city size) separately for the two samples. Moreover, we report these data both after poststratification (ie, after applying sample weights; table 1) as well as before poststratification (ie, the unweighted raw values; online supplementary table S1). The poststratification weights were computed separately for the two samples and were used to fine tune the representativeness of the quota-driven samples for the respective populations. We incorporated them for reporting the sociodemographic characteristics (using the R-package survey19) as well as in all beta regression analyses described below. Because income levels, educational levels and city sizes differed between the two countries, we created separate sets of bins for each country such that the corresponding bins contained comparable numbers of respondents for both countries. 10.1136/bmjopen-2018-022289.supp1Supplementary file 1 Table 1 Sociodemographic characteristics of the two samples after poststratification Variable Levels (Germany/Switzerland) Germany Switzerland Sample size n=1007 n=1003 Perspective: surrogate n=505 (50%) n=501 (50%) Female n=517 (51%) n=507 (51%) Age (years) M=48 (SD=18.4) M=43.6 (SD=15.6) Household size M=2.5 (SD=1.6) M=2.8 (SD=1.7) Employed n=574 (57%) n=694 (69%) Education  0 Compulsory education n=568 (60%) n=580 (58%)  1 Upper secondary education n=245 (26%) n=115 (12%)  2 College n=129 (14%) n=308 (31%) Income  0 <€1500/