- Email: [email protected]
Reframing risk part II: Methods for improving medical risk communication
Reframing risk part II: Methods for improving medical risk communication Benjamin K. Stoff, MD,a,b and Robert A. Swerlick, MDa Atlanta, Georgia
CASE SCENARIO After a thorough discussion about rituximab, Mrs M expresses concern about a serious infection. Dr Blister reviews the medical literature to discover that, according to data from clinical trials, the risk of serious infection in patients treated with rituximab ranges from 2.5% to 12%.1,2 In A. B. C. D.
conveying this risk to Mrs M, Dr Blister should say or do which of the following: ‘‘The risk of serious infection after treatment with rituximab is low.’’ ‘‘The rate of serious infection after treatment with rituximab is 2.5% to 12%.’’ ‘‘25 to 120 of 1000 Patients treated with rituximab acquire a serious infection.’’ Construct a graphic depiction of the proportion of patients treated with rituximab who develop a serious infection.
DISCUSSION Adequate communication of risks associated with treatment is required by bioethical principles and the law, as discussed in Part I. Although some legal commentary exists about which risks to disclose, there is little guidance on how to communicate them effectively. A major hindrance to comprehension of risk is poor numeric literacy, or numeracy.3 Innumeracy affects not only patients but health care providers as well.4 Many people have particular difficulty with understanding probabilities expressed as fractions or percentages.5 To counter this, research suggests that stating risks in terms of naturally occurring frequencies improves comprehension, even more so for the elderly and those with poor numeracy at baseline than for others.5 To convey a risk in a natural frequency format, simply convert the percentage into a whole number of affected individuals out of a seemingly naturally occurring population. For example, if the risk of a serious cardiac event after rituximab treatment is approximately 1%, then
From the Department of Dermatology, Emory University School of Medicine,a and Emory Center for Ethics.b Funding sources: None. Conflicts of interest: None declared. Correspondence to: Benjamin K. Stoff, MD, Department of Dermatology, Emory University School of Medicine, 1525 Clifton Rd NE, Atlanta, GA 30312. E-mail: [email protected].
natural frequency format would convey this risk as 10 out of 1000. Another helpful technique for conveying risk to patients, particularly those with poor numeracy, is to use visual depictions of probabilities. Several strategies for visual representation of medical risk have been offered in the literature.6 In one example, a group of 100 or 1000 human forms is presented on a diagram (Fig 1). The provider then highlights the proportion of the forms affected by the risk. Not only is this technique beneficial because it avoids numbers altogether, it also may be used to convey multiple risks or combinations of risks and benefits simultaneously. The latter feature may help to combat the effects of framing (see below). Figures have also been used to provide context for patients by placing risks on a scale with other familiar, or everyday, risks.6 For example, the risk of hypersensitivity to rituximab could be placed on a scale (linear or logarithmic) with more familiar risks like that of death in a motor vehicle accident or being struck by lightning.
J Am Acad Dermatol 2013;69:637-9. 0190-9622/$36.00 Ó 2013 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2013.02.026
637
638 Stoff and Swerlick
Fig 1. Graphic depiction of 10% risk (derived from Paling9).
The health care provider may also unwittingly preclude adequate comprehension of risk by the patient through the use of imprecise language. Precise numeric definitions of familiar terms expressing probability, such as ‘‘common’’ and ‘‘rare’’ for example, appear to be lacking. A compelling case for this kind of imprecision was made through a review of physician testimony in court.7 Investigators recorded physicians’ verbal expressions of frequency, such as ‘‘common’’ and ‘‘rare,’’ and compared those terms to the actual numbers to which the expressions referred. Physicians used terms like ‘‘low risk’’ to describe risks ranging from 1 in 10 to 1 in
ANALYSIS OF CASE SCENARIO Simply mentioning that the risk of serious infection after rituximab is low, as suggested by choice A, may lead to miscommunication between Dr Blister and Mrs M. As mentioned above, there is substantial imprecision associated with the term ‘‘low’’ in the context of medical risk.7 It is conceivable that Dr Blister may consider a 10% risk low but Mrs M would consider the same risk high. Lack of precision in language, therefore, makes choice A incorrect. Choice B, which conveys the risk of serious infection as a percentage, is more precise than choice A. However, if a patient or health care provider suffers from poor numeracy, he or she may have difficulty understanding probabilities presented in this format. In that case, converting risks from percentages to whole number natural frequencies leads to enhanced
J AM ACAD DERMATOL
OCTOBER 2013
100,000,000. As a result, some have advocated standardizing the definitions of these familiar terms or abandoning them altogether.8 Until standard definitions are established and agreed upon, risk experts advise using specific numbers or ranges of numbers rather than these terms to express probability.9 Another problem encountered by providers in conveying risk to patients involves framing. In risk framing, different formats, often statistical, for depicting the same risk may lead to very different responses from patients. In a classic example of the effects of framing, information on risk of a hypothetical antihypertensive medication was communicated to primary care patients in the following formats: relative risk, absolute risk, number needed to treat, and personal probability of harm/benefit.10 There was a more than 2-fold difference in patients’ likelihood to accept the medication, depending on how the risk was framed. There is also compelling evidence to suggest strong and consistent effects of other types of risk framing, such as gains versus losses, immediate versus delayed, and novel versus familiar.8 Framing effects are difficult to fully account for, given that, no matter how the risk is stated, there is likely to be some influence on the patient. One strategy is to present risk information using as many frames as possible. As mentioned above, visual depictions of proportions and risk scales maybe helpful in accomplishing this. For example, potential gains and losses or multiple familiar and unfamiliar risks may be conveyed on the same figure.
understanding.5 Therefore, B is not the best choice. Choice C states the risk of serious infection as a natural frequency, using whole numbers and a seemingly natural population size. This format improves comprehension among patients, especially the low numerate and elderly. Thus, choice C is acceptable. However, it is still subject to framing effects. Conveying risk of serious infection to Mrs M using a figure is also acceptable and may be most beneficial in the case of patients or providers with low numeracy. A well-constructed figure will allow Dr Blister to depict risk proportions without using numbers. Further, she will be able to communicate multiple risks, and perhaps benefits, on the same figure, thereby making efforts to account for the effects of framing.
J AM ACAD DERMATOL
Stoff and Swerlick 639
VOLUME 69, NUMBER 4
Bottom line: Communication of risk presents a formidable challenge. Barriers include poor numeracy, imprecise language, and framing. Use of natural frequencies and well-designed figures may improve patient comprehension and promote patient autonomy. REFERENCES 1. Le Roux-Villet C, Prost-Squarcioni C, Alexandre M, Caux F, Pascal F, Doan S, et al. Rituximab for patients with refractory mucous membrane pemphigoid. Arch Dermatol 2011;147: 843-9. 2. Rafailidis PI, Kakisi OK, Vardakas K, Falagas ME. Infectious complications of monoclonal antibodies used in cancer therapy: a systematic review of the evidence from randomized controlled trials. Cancer 2007;109:2182-9. 3. Schwartz LM, Woloshin S, Black WC, Welch HG. The role of numeracy in understanding the benefit of screening mammography. Ann Intern Med 1997;127:966-72. 4. Anderson BL, Obrecht NA, Chapman GB, Driscoll DA, Schulkin J. Physicians’ communication of Down syndrome screening
5.
6.
7.
8.
9.
10.
test results: the influence of physician numeracy. Genet Med 2011;13:744-9. Galesic M, Gigerenzer G, Straubinger N. Natural frequencies help older adults and people with low numeracy to evaluate medical screening tests. Med Decis Making 2009;29:368-71. Siegrist M, Orlow P, Keller C. The effect of graphical and numerical presentation of hypothetical prenatal diagnosis results on risk perception. Med Decis Making 2008;28:567-74. Merz JF, Druzdzel MJ, Mazur DJ. Verbal expressions of probability in informed consent litigation. Med Decis Making 1991; 11:273-81. Moore RA, Derry S, McQuay HJ, Paling J. What do we know about communicating risk? A brief review and suggestion for contextualizing serious, but rare, risk, and the example of cox2 selective and non-selective NSAIDs. Arthritis Res Ther 2008; 10:R20. Paling J. Helping patients understand risks: 7 simple strategies for successful communication. 2nd ed. Gainesville (FL): Risk Communication Institute; 2006. Misselbrook D, Armstrong D. Patients’ responses to risk information about the benefits of treating hypertension. Br J Gen Pract 2001;51:276-9.
CASE SCENARIO After a thorough discussion about rituximab, Mrs M expresses concern about a serious infection. Dr Blister reviews the medical literature to discover that, according to data from clinical trials, the risk of serious infection in patients treated with rituximab ranges from 2.5% to 12%.1,2 In A. B. C. D.
conveying this risk to Mrs M, Dr Blister should say or do which of the following: ‘‘The risk of serious infection after treatment with rituximab is low.’’ ‘‘The rate of serious infection after treatment with rituximab is 2.5% to 12%.’’ ‘‘25 to 120 of 1000 Patients treated with rituximab acquire a serious infection.’’ Construct a graphic depiction of the proportion of patients treated with rituximab who develop a serious infection.
DISCUSSION Adequate communication of risks associated with treatment is required by bioethical principles and the law, as discussed in Part I. Although some legal commentary exists about which risks to disclose, there is little guidance on how to communicate them effectively. A major hindrance to comprehension of risk is poor numeric literacy, or numeracy.3 Innumeracy affects not only patients but health care providers as well.4 Many people have particular difficulty with understanding probabilities expressed as fractions or percentages.5 To counter this, research suggests that stating risks in terms of naturally occurring frequencies improves comprehension, even more so for the elderly and those with poor numeracy at baseline than for others.5 To convey a risk in a natural frequency format, simply convert the percentage into a whole number of affected individuals out of a seemingly naturally occurring population. For example, if the risk of a serious cardiac event after rituximab treatment is approximately 1%, then
From the Department of Dermatology, Emory University School of Medicine,a and Emory Center for Ethics.b Funding sources: None. Conflicts of interest: None declared. Correspondence to: Benjamin K. Stoff, MD, Department of Dermatology, Emory University School of Medicine, 1525 Clifton Rd NE, Atlanta, GA 30312. E-mail: [email protected].
natural frequency format would convey this risk as 10 out of 1000. Another helpful technique for conveying risk to patients, particularly those with poor numeracy, is to use visual depictions of probabilities. Several strategies for visual representation of medical risk have been offered in the literature.6 In one example, a group of 100 or 1000 human forms is presented on a diagram (Fig 1). The provider then highlights the proportion of the forms affected by the risk. Not only is this technique beneficial because it avoids numbers altogether, it also may be used to convey multiple risks or combinations of risks and benefits simultaneously. The latter feature may help to combat the effects of framing (see below). Figures have also been used to provide context for patients by placing risks on a scale with other familiar, or everyday, risks.6 For example, the risk of hypersensitivity to rituximab could be placed on a scale (linear or logarithmic) with more familiar risks like that of death in a motor vehicle accident or being struck by lightning.
J Am Acad Dermatol 2013;69:637-9. 0190-9622/$36.00 Ó 2013 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2013.02.026
637
638 Stoff and Swerlick
Fig 1. Graphic depiction of 10% risk (derived from Paling9).
The health care provider may also unwittingly preclude adequate comprehension of risk by the patient through the use of imprecise language. Precise numeric definitions of familiar terms expressing probability, such as ‘‘common’’ and ‘‘rare’’ for example, appear to be lacking. A compelling case for this kind of imprecision was made through a review of physician testimony in court.7 Investigators recorded physicians’ verbal expressions of frequency, such as ‘‘common’’ and ‘‘rare,’’ and compared those terms to the actual numbers to which the expressions referred. Physicians used terms like ‘‘low risk’’ to describe risks ranging from 1 in 10 to 1 in
ANALYSIS OF CASE SCENARIO Simply mentioning that the risk of serious infection after rituximab is low, as suggested by choice A, may lead to miscommunication between Dr Blister and Mrs M. As mentioned above, there is substantial imprecision associated with the term ‘‘low’’ in the context of medical risk.7 It is conceivable that Dr Blister may consider a 10% risk low but Mrs M would consider the same risk high. Lack of precision in language, therefore, makes choice A incorrect. Choice B, which conveys the risk of serious infection as a percentage, is more precise than choice A. However, if a patient or health care provider suffers from poor numeracy, he or she may have difficulty understanding probabilities presented in this format. In that case, converting risks from percentages to whole number natural frequencies leads to enhanced
J AM ACAD DERMATOL
OCTOBER 2013
100,000,000. As a result, some have advocated standardizing the definitions of these familiar terms or abandoning them altogether.8 Until standard definitions are established and agreed upon, risk experts advise using specific numbers or ranges of numbers rather than these terms to express probability.9 Another problem encountered by providers in conveying risk to patients involves framing. In risk framing, different formats, often statistical, for depicting the same risk may lead to very different responses from patients. In a classic example of the effects of framing, information on risk of a hypothetical antihypertensive medication was communicated to primary care patients in the following formats: relative risk, absolute risk, number needed to treat, and personal probability of harm/benefit.10 There was a more than 2-fold difference in patients’ likelihood to accept the medication, depending on how the risk was framed. There is also compelling evidence to suggest strong and consistent effects of other types of risk framing, such as gains versus losses, immediate versus delayed, and novel versus familiar.8 Framing effects are difficult to fully account for, given that, no matter how the risk is stated, there is likely to be some influence on the patient. One strategy is to present risk information using as many frames as possible. As mentioned above, visual depictions of proportions and risk scales maybe helpful in accomplishing this. For example, potential gains and losses or multiple familiar and unfamiliar risks may be conveyed on the same figure.
understanding.5 Therefore, B is not the best choice. Choice C states the risk of serious infection as a natural frequency, using whole numbers and a seemingly natural population size. This format improves comprehension among patients, especially the low numerate and elderly. Thus, choice C is acceptable. However, it is still subject to framing effects. Conveying risk of serious infection to Mrs M using a figure is also acceptable and may be most beneficial in the case of patients or providers with low numeracy. A well-constructed figure will allow Dr Blister to depict risk proportions without using numbers. Further, she will be able to communicate multiple risks, and perhaps benefits, on the same figure, thereby making efforts to account for the effects of framing.
J AM ACAD DERMATOL
Stoff and Swerlick 639
VOLUME 69, NUMBER 4
Bottom line: Communication of risk presents a formidable challenge. Barriers include poor numeracy, imprecise language, and framing. Use of natural frequencies and well-designed figures may improve patient comprehension and promote patient autonomy. REFERENCES 1. Le Roux-Villet C, Prost-Squarcioni C, Alexandre M, Caux F, Pascal F, Doan S, et al. Rituximab for patients with refractory mucous membrane pemphigoid. Arch Dermatol 2011;147: 843-9. 2. Rafailidis PI, Kakisi OK, Vardakas K, Falagas ME. Infectious complications of monoclonal antibodies used in cancer therapy: a systematic review of the evidence from randomized controlled trials. Cancer 2007;109:2182-9. 3. Schwartz LM, Woloshin S, Black WC, Welch HG. The role of numeracy in understanding the benefit of screening mammography. Ann Intern Med 1997;127:966-72. 4. Anderson BL, Obrecht NA, Chapman GB, Driscoll DA, Schulkin J. Physicians’ communication of Down syndrome screening
5.
6.
7.
8.
9.
10.
test results: the influence of physician numeracy. Genet Med 2011;13:744-9. Galesic M, Gigerenzer G, Straubinger N. Natural frequencies help older adults and people with low numeracy to evaluate medical screening tests. Med Decis Making 2009;29:368-71. Siegrist M, Orlow P, Keller C. The effect of graphical and numerical presentation of hypothetical prenatal diagnosis results on risk perception. Med Decis Making 2008;28:567-74. Merz JF, Druzdzel MJ, Mazur DJ. Verbal expressions of probability in informed consent litigation. Med Decis Making 1991; 11:273-81. Moore RA, Derry S, McQuay HJ, Paling J. What do we know about communicating risk? A brief review and suggestion for contextualizing serious, but rare, risk, and the example of cox2 selective and non-selective NSAIDs. Arthritis Res Ther 2008; 10:R20. Paling J. Helping patients understand risks: 7 simple strategies for successful communication. 2nd ed. Gainesville (FL): Risk Communication Institute; 2006. Misselbrook D, Armstrong D. Patients’ responses to risk information about the benefits of treating hypertension. Br J Gen Pract 2001;51:276-9.