Evidence-Based Risk Communication A Systematic Review Daniella A. Zipkin, MD; Craig A. Umscheid, MD, MS; Nancy L. Keating, MD, MPH; Elizabeth Allen, MD; KoKo Aung, MD, MPH; Rebecca Beyth, MD, MSc; Scott Kaatz, DO, MSc; Devin M. Mann, MD, MS; Jeremy B. Sussman, MD, MS; Deborah Korenstein, MD; Connie Schardt, MLS; Avishek Nagi, MS; Richard Sloane, MPH; and David A. Feldstein, MD Background: Effective communication of risks and benefits to pa- tients is critical for shared decision making. Purpose: To review the comparative effectiveness of methods of communicating probabilistic information to patients that maximize their cognitive and behavioral outcomes. Data Sources: PubMed (1966 to March 2014) and CINAHL, EMBASE, and the Cochrane Central Register of Controlled Trials (1966 to December 2011) using several keywords and structured terms. Study Selection: Prospective or cross-sectional studies that re- cruited patients or healthy volunteers and compared any method of communicating probabilistic information with another method. Data Extraction: Two independent reviewers extracted study char- acteristics and assessed risk of bias. Data Synthesis: Eighty-four articles, representing 91 unique stud- ies, evaluated various methods of numerical and visual risk display across several risk scenarios and with diverse outcome measures. Studies showed that visual aids (icon arrays and bar graphs) im- proved patients’ understanding and satisfaction. Presentations in- cluding absolute risk reductions were better than those including relative risk reductions for maximizing accuracy and seemed less likely than presentations with relative risk reductions to influence decisions to accept therapy. The presentation of numbers needed to treat reduced understanding. Comparative effects of presenta- tions of frequencies (such as 1 in 5) versus event rates (percent- ages, such as 20%) were inconclusive. Limitation: Most studies were small and highly variable in terms of setting, context, and methods of administering interventions. Conclusion: Visual aids and absolute risk formats can improve patients’ understanding of probabilistic information, whereas num- bers needed to treat can lessen their understanding. Due to study heterogeneity, the superiority of any single method for conveying probabilistic information is not established, but there are several good options to help clinicians communicate with patients. Primary Funding Source: None. Ann Intern Med. 2014;161:270-280. doi:10.7326/M14-0295 www.annals.org For author affiliations, see end of text. S hared decision making is a collaborative process that allows patients and medical professionals to consider the best scientific evidence available, along with patients’ values and preferences, to make health care decisions (1). A recent Institute of Medicine report concluded that al- though “people desire a patient experience that includes deep engagement in shared decision making,” there are gaps between what patients want and what they get (2). For patients to get the experience they want, providers must effectively communicate evidence about benefits and harms. To improve the decision-making process, the Institute of Medicine recommended development and dissemina- tion of high-quality communication tools (2). New tools, however, must match patients’ numerical abilities, which are often limited. For example, in one study, as many as 40% of high school graduates could not perform basic numerical operations, such as converting 1% of 1000 to 10 of 1000. This “collective statistical illiteracy” is a major barrier to the interpretation of health statistics (3). Physi- cians may also find statistical information difficult to inter- pret and explain (4). Existing literature about methods of communicating benefits and harms is broad. One review, based on 19 studies, concluded that the choice of a specific graphic is not as important as whether the graphic frames the fre- quency of an event with a visual representation of the total population in which it occurs (5). Another review, involv- ing a limited literature search, found that comprehension improved when using frequencies (such as 1 in 5) instead of event rates (such as 20%) and using absolute risk reduc- tions (ARRs) instead of relative risk reductions (RRRs) (6). The review did not assess affective outcomes, such as pa- tient satisfaction, and behavioral outcomes, such as changes in decision making. Yet another review identified strong evidence that patients misinterpret RRRs and supported the effectiveness of graphs in communicating harms (7). However, they did not examine the comparative effective- ness of such approaches. More narrowly focused Cochrane reviews examined the communication of risk specific to screening tests (8, 9); numerical presentations, such as ARRs, RRRs, and numbers needed to treat (NNTs) (10); and effects of decision aids (11). An expert commentary about effective risk communication recommended using plain language, icon arrays, and absolute risks and provid- ing time intervals with risk information (12). A group of experts identified 11 key components of risk communica- tion, including presenting numerical estimates in context See also: Web-Only Supplements Annals of Internal Medicine Research and Reporting Methods 270 © 2014 American College of Physicians Downloaded From: http://annals.org/ by a Penn State University Hershey User on 02/04/2015