Presenter: Corey Siegel, MD, Director of the Inflammatory Bowel Disease Center, Dartmouth-Hitchcock Medical Center, Lebanon NH
Like other chronic inflammatory conditions, inflammatory bowel disease (IBD) has been revolutionized by the advent of biologic agents that fundamentally alter the inappropriate inflammatory response. The most potent of these are the biologic agents, infliximab, adalimumab, certolizumab pegol, and natalizumab. They also have the most dangerous side-effect profile. All immunomodulators—including the older agents 6-mercaptopurine (6-MP) and azathioprine (AZA)—can suppress normal immune function, and are therefore associated with a non-zero risk of serious infection and malignant neoplasm. Because of this, patients are sometime reluctant to treat Crohn disease and ulcerative colitis aggressively. Although the risks are low, many practitioners struggle to help patients put the risk into perspective.
Crohn disease and ulcerative colitis are serious intestinal conditions that can be dangerous, sometimes requiring major surgery or colostomy. Is the patient willing to take a small risk to prevent this? It turns out that the answer depends on how the question is framed. The ideas generated in this session are applicable not just to gastroenterology but to many risk discussions in primary care as well.
Studies have shown a wide range of understanding of the vague terms “rare,” and “common.” One study presented subjects with questions like:
• How often does a “rare” event happen in a year? Answers ranged from “3 per million” to “20%” (median 2%)
• How often does a “common” event happen in a year? Answers ranged from 5% to 76% (median 30%).
Dr Siegel presented other intriguing data:
• Half of patients were unable to convert 1% to 10 in 1000
• 80% of patients were unable to convert 1 in 1000 to 0.1%
• Patients had difficulty in determining which is the higher risk: 1 in 27, or 1 in 37
These data have been replicated with highly educated subjects, including medical students. Now superimpose these numeracy deficiencies onto the office visit where an anxious patient is being presented with alarming side-effect possibilities, and is asking for probabilities that the misfortune will befall him or her. Dr Siegel had practical advice for helping patients put these numbers into perspective.
1. Don’t withhold probability numbers for adverse events: If you do, the patient will access them without you, on the Internet. At that point you won’t be there to put the risk into perspective.
2. Present the patient absolute risk numbers for comparison, rather than relative risk inherent in two choices: For a patient choosing between two modalities—the first with a 1 in 100 risk and the second with a 2 in 100 risk of serious complication—the use of relative risk will be unnecessarily alarming because it suggests a doubling of risk. Given the low risk in the first place, doubling of that risk continues to present an unlikely outcome and should be put into perspective of the risk of non-treatment (eg, 10% chance of colostomy over some time-frame?). Present the risk as a movement from 1% to 2%, not a 100% increase (both are statistically true).
3. Avoid decimals: Patients at varying levels of education struggle to make sense of these.
4. Keep common denominators: In other words, some number out of 100 (or 1000).
5. Use visual aids: Turning numbers into pictures, Dr Siegel uses printed sheets with large numbers of stick figures, manually highlighting the fraction that will be affected by a side effect.
6. Give perspective to other disease and life risks: As above, note the risks of non-treatment, but also the risk of auto accident, sports injuries, etc. This allows the patient to put the risk into perspective of other risks they are willing to take to achieve some practical benefit.
The remainder of the lecture concerned specific risk-benefits of various drugs for IBD, whose choice will likely be made by a specialist and the patient. But primary care providers face these kinds of risk-benefit discussions with their patients every day. This session contained some excellent tips for dealing with them. It’s crucially important when dealing with patients whose most important risk is from non-treatment of their primary disease.