When I give presentations on the guideline development process of the U.S. Preventive Services Task Force, a question I'm often asked is how many votes of the 16-member panel are needed to approve a recommendation statement. The answer is a two-thirds majority, with a minimum of 10 votes in favor in case of absences or conflict-of-interest recusals. In reality, though, during the four years I attended Task Force meetings, I can't recall a statement passing without overwhelming (15-1 or 14-2) or, more commonly, unanimous support. The feeling among members seemed to be that the lack of a strong consensus on a recommendation suggested that there was something missing about the way they were approaching the evidence.
In contrast, since the vacancy created by the death of associate justice Antonin Scalia, the Supreme Court of the United States has issued several evenly split decisions, with their most recent tie effectively affirming a lower court decision that blocked President Obama's 2014 executive order to shield some undocumented immigrants from deportation. In this case, the Court issued no opinion at all. However, when majorities have decided other cases, the Court provided justices in the minority the option of publishing dissenting opinions, whose legal reasoning sometimes informed future decisions.
Minority opinions rarely accompany medical guidelines. In an unusual case, after the JNC 8 committee published its guideline for management of high blood pressure in adults, five former panel members who disagreed with the guideline's target systolic blood pressure of 150 mm Hg in persons aged 60 years or older formally published their minority view. Even then, this dissenting report appeared some time later, in a different journal than the original guideline.
In a recent article in Mayo Clinic Proceedings, Dr. Daniel Musher, a professor of medicine and infectious diseases at Baylor College of Medicine, made the case for regularly publishing dissenting opinions in medical guidelines. He cited his experience as a member of the Advisory Committee on Immunization Practices (ACIP) working group that recommended the use of 13-valent pneumococcal conjugate vaccine (PCV13) in adults 65 years and older, despite his strong disagreement. As is standard process for the ACIP and most guideline panels, he did not have the opportunity to voice his dissenting opinion and rationale in the text of the guideline. His view did not see publication until more than 18 months later, after the new recommendation had been largely implemented into clinical practice. Dr. Musher wrote:
The perceived problems with publishing dissenting opinions are that this practice would (1) cause confusion within the medical community and (2) diminish the force of the recommendations. Regarding the former, the current situation, in which dissent is not included but in which subsequent articles dispute the formal recommendations or different professional societies publish divergent guidelines, is amply confusing—witness the differing guidelines for screening for breast, lung, or prostate cancer. It defies reason to believe that every member of the American Cancer Society's committee thought that breast cancer screening should begin at age 40 years, whereas all who participated in the US Preventive Services Task Force agreed that screening should wait until age 50 years. Inclusion of dissenting opinions in the final version of published guidelines may well have reduced polarization and confusion by bringing dissent into the recommendation process.
I can't testify to the presence or absence of internal discord on the panels that produced the 2015 ACS or 2016 USPSTF guidelines on breast cancer screening, but my best recollection of the July 2008 meeting where the USPSTF first voted to recommend routine mammography starting at age 50 is that, contrary to Dr. Musher's suggestion, there was no minority view. When there is one, I agree with him and the Slow Medicine bloggers that making a forum available to describe conflicts that occurred within the guideline narrative (including all of the various options that were considered and later discarded) could reduce the intensity of second-guessing and better inform clinicians about the guideline's nuances and potential limitations. Now that I have experience as a voting member of American Academy of Family Physicians guideline panels, though, I wonder if the explication of dissents belongs in the guideline itself, rather than as a separate stand-alone perspective.
Would the airing of minority views within medical guidelines provide useful perspectives for patients, clinicians, or policymakers, or are conflicting guidelines from different organizations already confusing enough as it is?