Risky Business, Part 2: Communicating Medical Risks to Patients and Parents

Put yourself in the place of the parent of a 15-month-old girl who is being seen by her pediatrician for a well-child visit and routine immunizations. Listen to 2 different ways the pediatrician might describe the potential risk of your child's having a seizure caused by the combined measles-mumps- rubella-varicella (MMRV) vaccine.

• Risk description A: "Nine thousand nine hundred ninety-nine out of every 10,000 children who get the MMRV vaccine do just fine. I wouldn't worry about it."

• Risk description B: "For every thousand MMRV vaccines we give, one unfortunate child has a frightening seizure that requires medical attention."

As a parent, how would you feel about subjecting your child to this risk after each of these descriptions? Would you be willing to have your child vaccinated? Although the same risk has been described, the 2 descriptions (which include the physician's own value judgment) are so different that the danger of the vaccine for your child would be perceived very differently. The difference in the perception of the risk would then influence your decision about whether to have your child immunized.

Pediatricians help patients and parents make decisions many times each day, and each of these decisions requires a weighing of risks and benefits. In a previous article, we reviewed the various ways in which researchers express medical risk.¹ Once a clinician has a sufficient understanding of the risks associated with a disease or treatment, he or she must then communicate this information to the patient or the patient's family in a manner that is as thorough, understandable, and unbiased as possible. The ability to communicate information about risk effectively to patients and parents is a valuable asset in a pediatric practice. In this article, we describe strategies for explaining concepts of medical risk, and we identify potential pitfalls in the communication of risk, along with suggestions for avoiding them.

DIFFERENT STRATEGIES FOR EXPLAINING RISK

People learn in different ways. Some are visual learners, some are verbal learners, some are physical learners, some are logical learners,and so forth. Similarly, individual patients and parents will best understand data about risk when this information is presented in different ways. For example, some patients and parents prefer and understand numerical measures of risk, whereas others prefer verbal descriptions of risk. The job of the pediatrician is to present the information in a manner that is easily understood. Some possible strategies for presenting risk information include numerical explanations, verbal descriptions, visual displays, and comparisons with equivalent risks. Whichever strategy you decide to use, keep in mind the significant effect that "framing" has on how the explanation is received (see Box).

Numerical explanations. People are accustomed to hearing risk described in numerical terms, and many absorb the information best when it is presented in this traditional manner. If you decide to use a numerical explanation, be sure to choose the particular way of expressing risk that is most appropriate for the situation and persons involved. Sometimes you may use absolute numbers in a simple ratio, at other times relative risk, and at still other times, attributable risk or the number needed to harm. Our first article described in detail the significance of these various expressions of risk.¹ If you decide to use an expression of relative risk, keep in mind that interpretation of its significance depends on the magnitude of the baseline risk. You may prefer to use the attributable risk or number needed to harm because, although these measures may require you to perform a few calculations with the data presented in a research article, they have the advantage of telling the frequency of adverse outcomes attributable to the risky exposure.

Verbal descriptors. Many patients are more comfortable with words than with numbers. However, pediatricians who describe risk for patients and parents using qualitative verbal terms recognize the inherent lack of precision of verbal descriptors. In fact, physicians may do no better than patients at interpreting verbal expressions of risk. In one small survey, physicians' estimates of the numerical probability suggested by 30 verbal expressions (such as "likely," "doubtful," and "sometimes") were highly variable.²

In an attempt to standardize verbal descriptions of risk, the use of agreed-on verbal scales of risk has been proposed. One example is the scale of verbal descriptors developed by the European Commission to describe the probability of an adverse drug reaction (Table 1). Unfortunately, many patients grossly overestimate the risks of adverse drug reactions when the risks are presented using this scale.³

Table 1

Visual descriptors. Because of the difficulties involved in communicating risks using numbers or words, graphic tools have been developed to present risk information to patients and parents. Some of these tools are fairly complex to construct and individualize, but others are easier to use and interpret. A pie diagram, for example, is familiar, is simple to construct with pen and paper, and can be used to depict the likelihood of 2 or more different outcomes. Another tool that is relatively easy for clinicians to use in daily practice is a grid of graphic symbols (eg, happy faces, infants, or theater seats) on which a precise number of symbols can be colored in or crossed out to represent the number of patients who are expected to experience the outcome of interest. Such grids can be constructed on a piece of paper or on a computer screen using a special program. ⁴Figures 1 and 2 provide examples of visual representations of risk that a pediatrician may be able to draw quickly in the examining room.

Figure 1 – Use of a circle to construct a pie graph illustrating the 1-in-4 risk of fever following receipt of the diphtheria-tetanusacellular pertussis vaccine.

¹⁴

Figure 2 – Use of a 10 ×10 grid containing 100 boxes to illustrate a 1-in-25 risk of rash following receipt of the varicella vaccine.

¹⁵

Some clinicians use verbal descriptions of a visual tool. For example, to express a risk of 1 in 100 that an adverse outcome will occur, they might say, "If I took a jar and put 100 white marbles in it and 1 blue marble, what is the likelihood of you reaching in and pulling out the blue marble?" When asked this question, some people might comment that they would try to find a way to push the blue marble to the bottom of the jar; however, such a response could be used to initiate a fruitful discussion about ways to minimize risk.

Equivalent risks. Another means of communicating the magnitude of a  medical risk is to compare it to the risk of some unrelated event. For example, the risk that a child whose parents both have sickle cell trait will have sickle cell disease-a risk of 1 in 4-could be likened to the probability of getting 2 heads in 2 consecutive coin tosses. A 1 in 6 million risk of death from a surgical procedure is a number that is too small for most people to understand in a personal, tangible way. This risk could be compared, however, to the likelihood of being killed by a lightning strike in the next year (also a chance of about 1 in 6 million).⁵ Keep in mind, however, that risk data represent averages and not individual risks. A golfer or a roofer might have a higher risk of dying from a lightning strike than would a computer programmer who rarely goes outside in the rain. In addition, it is important to be cautious about using equivalent risks, lest you be perceived as trivializing medical decisions by comparing them with rare random events.

Use of multiple strategies. One suggestion for ensuring that a patient or parent has understood the risk involved in a certain situation is to express the risk in several different ways. For example, you might use verbal descriptors, estimated numbers, and even visual aids to portray the probabilities. You could use absolute numbers as well as relative risk, and you could frame the risk in both positive and negative terms. However, using multiple methods is potentially a very time-consuming strategy, and it may give the patient too much information. When presented with more and more information, patients tend to become increasingly wary of the intervention that is being discussed and to make more conservative decisions.⁶

POTENTIAL PITFALLS IN THE COMMUNICATION OF RISK

Unconsciously spinning the information. How we present information about the risk of an outcome or a treatment can have a large impact on how this risk is perceived. The 2 lines in the familiar optical illusion pictured in Figure 3 are exactly the same length, but we perceive the top line to be longer because of how it is presented. Similarly, our body language, the inflection in our voices, and our choice of words can affect how the information we are conveying is interpreted. The example given at the beginning of this article illustrates how the way in which information is presented to parents can influence the message they hear, and how these different messages can, in turn, influence parents' medical decisions. Thus, pediatricians need to be aware of how they may unconsciously "spin" the risk information they present to patients and parents.

Figure 3 – Which line is longer?

In situations in which we are asked by a family to give our advice regarding an intervention, it may be entirely appropriate to express our opinion and to be directive. However, this is probably best done very explicitly; for example, "In my opinion, the risk of an adverse outcome is so small that it is outweighed by the anticipated benefit of the treatment." In most situations it is usually best to present the risk information in a neutral way ("just the facts") and let the patient and/or parent make an independent assessment of the risks and benefits followed by a medical decision based on this assessment.

Differences in how a given risk is perceived. Difficulties in communication may arise when the 2 parties have different perceptions of risks. Parents may be very concerned, for example, about a perceived (but unsubstantiated) risk of autism developing after their child receives the MMR vaccine. They may be worried very little about their child's acquiring any of these 3 infectious diseases, which seem like relics of a bygone era and with which they are totally unfamiliar (because, ironically, of the success of childhood immunization efforts). Pediatricians, on the other hand, may feel reassured by the lack of scientific evidence linking MMR vaccine with autism and thus be not at all concerned about this risk. On the other hand, they may be aware of recent surges of measles and mumps activity in the United States^7,8 and be much more worried that children who are not vaccinated may contract a vaccine-preventable illness with attendant risks of medical and public health complications.

Research suggests that patients tend to overestimate the risk of very rare adverse outcomes, especially when these rare events receive media attention, but be overly optimistic about their own personal risk for more likely events.9 People often see themselves as generally "lucky" or "unlucky," and these perceptions may cause them to underestimate or overestimate their own personal risks. Men and women often differ in the way that they perceive risk,¹⁰ so mothers and fathers may likewise respond differently to information about risks to their children.

Influence of emotion and experience. For many patients, assessment of risk is ultimately determined more by emotion than fact. Information about risk is always interpreted, by physician and patient, in the context of personal experience. For parents who have had a bad experience, perceptions of luck and risk are permanently altered. A parent may say something like, "They told me that cerebral palsy occurs in only 1 in 1000 newborns. That seemed like a really small number until Johnny was born with cerebral palsy. Now that this has happened to me, numbers don't mean anything." Altered perceptions of risk may sometimes occur in parents who have not themselves had a bad experience but who know other parents who have had such experiences.

The "chagrin factor." According to one theory, decisions are often made to minimize the likelihood of great regret. When making a clinical decision, some people place great weight on very rare but also very dangerous outcomes. This is sometimes referred to as avoiding a high "burden of risk" or simply as the "chagrin factor."¹¹ For example, a physician in whose patient Stevens- Johnson syndrome developed after being given a sulfa drug may choose a different antibiotic for his next patient because the burden of risk is perceived to be unacceptably high. Likewise, parents of a child with autism may wish to avoid any intervention that might increase their new infant's risk of autism, no matter how small this risk may be. To better understand the concept of the burden of risk, consider the effect a low burden of risk has on decision making. This can be seen in the purchase of a lottery ticket. A person reads that his chances of winning the lottery are 1 in 1000; this means that his chances of losing are 999 in 1000. However, because all he stands to lose is the dollar he spends on the ticket-a low burden of risk-he decides that the odds are "pretty good" and he buys the ticket.

When another's perception of risk is at odds with yours. As a physician, you may feel frustrated when patients or parents base medical decisions on perceptions of risk that seem irrational to you-for example, placing what strikes you as inordinate emphasis on an exceedingly rare outcome. However, if you have presented the risk information fairly and accurately, and you are comfortable that the patient or parent has understood this information, then you have done your job. It is important to remember that patients' and parents' choices reflect their own experiences, emotions, and values and are therefore valid decisions.

A FEW MORE SUGGESTIONS FOR EFFECTIVE DISCUSSIONS ABOUT RISK

Several tips for presenting risk information to patients and parents are presented in Table 2. Remember, of course, that discussions about risk should occur within the context of general principles crucial to the practice of medicine:

Table 2

• Seek medical information that is current and evidence-based.

• Acknowledge the limitations of medical knowledge and be comfortable sharing uncertainty.

• Listen attentively to your patients and invite them to become full partners in the decision-making process.

In situations where families get "stuck" in the decision-making process, it is often helpful to assess their past experiences with risk taking and decision making. Most people have made medical decisions in the past that involved risk taking. Were there any uncomfortable outcomes in this family's past, and what residual feelfeelings do they have about these? How are these past experiences impacting their current decision-making process? Bringing the past into the present may help the family understand their current difficulty in making choices.

We would like to thank Logan Karns, MS, for her helpful suggestions for this article.

The Effect of Framing on How Risks Are Perceived

Framing refers to the point of view from which risk information is presented-whether it is one of desirable outcomes or one of adverse outcomes. For example, if the mortality associated with a procedure is 1 in 1000 patients, this information could be framed in positive terms: "Almost everyone survives . . . 999 patients out of 1000 will live." Alternatively, this information could be framed in negative terms: "One patient in every thousand will die."

A recent study demonstrated the effect of positive versus negative framing on decision making.¹² The researchers presented volunteer subjects with a hypothetical vignette in which a pregnant woman is threatened with a preterm delivery at 23 weeks' gestation. The subjects' decisions about whether to resuscitate the newborn or provide only comfort care were strongly influenced by how prognostic information was framed. When the prognostic data were framed in positive terms, the subjects were more optimistic about the outcome and were more likely to choose resuscitation than they were when the same data were framed in negative terms.

A different kind of framing involves the presentation of information about potential losses or gains that might result from choosing or declining a medical procedure. For example, parents deciding whether to consent to a vesicourethrogram for their infant son with a urinary tract infection might have that information presented to them in terms of the risk of potential long-term loss of renal function if posterior urethral valves remained undiagnosed. Alternatively, this information could be presented in terms of the potential benefit of preserving renal function if more timely information allows earlier treatment. Framing information in terms of loss typically has a greater impact on patient uptake of procedures than does framing in terms of gain.¹³

Keep in mind that framing may inadvertently undermine a pediatrician's efforts to provide risk information that is nondirective. One strategy that can minimize such bias is to state the risks in terms of both positive and negative outcomes.

References:

1.

Hellems MA, Hayden GF. Risky business: what the numbers suggest and what they mean.

Consultant for Pediatricians.

2008;7:271-273.

1.

Bryant GD, Norman GR. Expressions of probability: words and numbers.

N Engl J Med.

1980;302: 411.

1.

Knapp P, Raynor DK, Berry DC. Comparison of two methods of presenting risk information to patients about the side effects of medicines.

Qual Saf Health Care

. 2004;13:176-180.

1.

For examples, see http://theillusionofcertainty.com/RCT/RCT.html, http://riskcomm.com/thumbnails.htm, and http://www.nntonline.net/ebm/visualrx/try.asp.

1.

National Safety Council. The odds of dying from . . . 2004. http://www.nsc.org/research/odds.aspx. Accessed September 24, 2008.

1.

Edwards A, Elwyn G. Understanding risk and lessons for clinical risk communication about treatment preferences.

Qual Health Care.

2001;10(suppl 1):i9-i13.

1.

Centers for Disease Control and Prevention (CDC). Measles-United States, January 1-April 25, 2008.

MMWR.

2008;57:494-498.

1.

Dayan GH, Quinlisk MP, Parker AA, et al. Recent resurgence of mumps in the United States.

N Engl J Med.

2008;358:1580-1589.

1.

Weinstein ND. Optimistic biases about personal risks. Science. 1989;246:1232-1233.

1.

McQueen A, Vernon SW, Meissner HI, Rakowski W. Risk perceptions and worry about cancer: does gender make a difference? J Health Commun. 2008; 13:56-79.

1.

Feinstein AR. The "chagrin factor" and qualitative decision analysis.

Arch Intern Med

1985;145: 1257-1259.

1.

Haward MF, Murphy RO, Lorenz JM. Message framing and perinatal decisions. Pediatrics. 2008;122: 109-118.

1.

Edwards A, Elwyn G, Mulley A. Explaining risks: turning numerical data into meaningful pictures.

BMJ

. 2002;324:827-830.

1.

Centers for Disease Control and Prevention (CDC). Diphtheria-Tetanus-Pertussis Vaccine Information Statement. http://www.cdc.gov/vaccines/ pubs/vis/downloads/vis-tdap.pdf. Published July 12, 2006. Accessed September 15, 2008.

1.

Centers for Disease Control and Prevention (CDC). Chickenpox Vaccine Information Statement. http://www.cdc.gov/vaccines/pubs/vis/downloads/ vis-varicella.pdf. Published March 13, 2008. Accessed September 15, 2008.