Most Physicians Overestimate Treatment Harms, Benefits

Marcia Frellick

August 29, 2016

Most internal medicine residents and attending physicians overestimate the benefits and harms of common interventions, according to a new survey.

Overall, physicians overestimated the benefits 79% of the time, and the harms 66%; attending physicians and residents were equally inaccurate. Mona Krouss, MD, from the University of Maryland Medical Center, Baltimore, and colleagues report their findings in a research letter published online August 29 in JAMA Internal Medicine.

The authors say overreliance on the role of P values may help explain part of the poor communication with patients about risk and harms.

"Poor ability to estimate frequency of benefit likely relates to medical education focusing only on treatments that are recommended, with a heavy emphasis on P values alone, rarely using more accurate assessments of treatment effect size or frequency with absolute risk reduction or number needed to treat," they write.

Dr Krouss and colleagues surveyed 117 internal medicine residents and attending physicians at two academic medical centers, including physicians working in primary care, hospital medicine, and specialty care. The response rate was 88.6%.

The survey contained 18 questions, 10 of which evaluated understanding of rates of benefits and harms of the interventions. The other eight questions assessed confidence in responses, use of statistical terms, and physicians' awareness of high-value care efforts.

In addition to inaccurate benefit/risk estimations, the authors found the respondents were not very confident in their responses. Most (67.5%) chose 4 on a scale from 1 to 10, where 10 was very confident. Physicians also underestimate how often most treatments have no effect, either harmful or beneficial, the researchers found.

The results also showed that fewer than half (44.8%) of the physicians had ever heard of the national Choosing Wisely campaign, which emphasizes high-value care, and less than half of those physicians were using it in patient care.

In an invited commentary, Anna L. Parks, MD, from the Department of Medicine, University of California, San Francisco, and Patrick G. O'Malley, MD, MPH, from the Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, write that communication with patients about risks and benefits is particularly important with low-value care, as health systems struggle to rein in costs.

The study highlights the need for better training for physicians in numeracy and communication skills, they say.

Among the examples in the study, when asked to estimate how often cancer is diagnosed among positive screening mammograms, only 16 of the 115 physicians who answered the question guessed the correct percentage range, which is 1% to 4.9%. The largest number (40) answered that cancer is diagnosed from 10% to 19.9% of the time.

Moreover, the editorialists note that interpretation of screening statistics is often inaccurate. "Most primary care physicians incorrectly interpret cancer screening statistics, believing that a screening test that improves detection rates or 5-year survival saves lives," they write.

When asked about alendronate's prevention rate of hip fractures in 50- to 70-year-olds with osteoporosis for longer than 5 years, only three of the 108 physicians who answered the question gave the correct answer (<1.0%). Six physicians answered that the prevention rate was from 45.0% to 69.9%.

"More attention to numeracy and shared decision-making communication skills will complement system interventions like deployment of effective [electronic medical record]-based decision support tools at the point of care," Dr Parks and Dr O'Malley write. "Physicians at all levels of training must take on the additional professional obligation of communicating risk and benefits clearly to achieve care that is both high-value and in line with patients' goals."

One coauthor reports editorial honoraria from Springer for serving as a book and journal editor and reports support from the Department of Veterans Affairs' Health Services Research and Development Service and the Agency for Healthcare Research and Quality. The remaining authors and editorialists have disclosed no relevant financial relationships.

JAMA Intern Med. Published online August 29, 2016. Letter extract, Commentary extract

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