Monday, July 1, 2013

Abandoning risk factor assessment for HIV and HCV

During my family medicine training, I was taught about the importance of risk factor assessment in deciding what screening tests to order for patients seeking preventive health care. The principle is simple: to minimize false positives and their consequences, don't perform screening tests on patients who are unlikely to have the condition. For the chronic, treatable infections HIV and hepatitis C (HCV), adhering to this principle meant getting comfortable with asking patients about sensitive issues such as current or past illicit drug use and sexual behavior. For the latter, one of my teachers suggested a script along these lines: "Are you having sex? With one person or more than one? Male, female, or both?" Affirmative answers might lead to additional questions about specific sexual practices. Although patients occasionally give misleading or dishonest answers, self-reported drug use and sexual behaviors are considered accurate enough that these have long been accepted outcomes in research studies.

Risk factors are powerful predictors: for example, a person who has never used injection drugs or had sex with anyone who used injection drugs has a negligible risk of harboring asymptomatic HCV infection.

Given the above, I was surprised to read that the U.S. Preventive Services Task Force now recommends routine one-time screening for HCV in all persons born between 1945 and 1965, regardless of risk factors. In a significant change from the draft statement released last November, which suggested selective screening in this age group based on a somewhat higher baseline HCV prevalence related to the popularity of injection drug use in the 1970s and 1980s, the USPSTF decided instead to endorse the CDC's 2012 guideline and make screening the default choice for patients in the Baby Boom generation. This new recommendation comes on the heels of the Task Force's recent decision to abandon a risk factor-based approach to HIV screening and instead (like the CDC) test everyone between the age of 15 to 65.

Asked about the rationale for the USPSTF's change of heart, which caught the American Academy of Family Physicians off guard, Vice-Chair Dr. Michael LeFevre said: "We got a lot of public comments (on the draft recommendation), and many of them suggested that risk-based screening would essentially be a greater burden (to those doing the screening) than a birth-cohort approach, at least for that age group." He went on to cite 4 new studies that he said swayed the Task Force's change from a "C" to a "B" level recommendation, but since only one of those studies (a cost-effectiveness analysis, not a clinical trial) had anything to do with birth cohort screening, the new evidence was window dressing. The main issue is that talking with older patients about risk factors, which I consider to be an essential part of my training and practice, was thought by the USPSTF to be too burdensome a task for primary care physicians.

How have we really reached the point in this country where getting to know patients well enough to individualize their preventive health care is now considered a burden, rather than good medical practice? Primary care is considered so straightforward in many circles that independent nurse practitioners are thought to be as capable as physicians, but, apparently, it's also so complicated that we can't bother clinicians with taking a medical history. Sure, family doctors are sometimes harried or overwhelmed or forget to ask questions, but it's hardly a given that those same doctors will suddenly start ordering HIV and HCV tests for every Baby Boomer who walks in the door. More likely, prompted by preventive medicine process "quality" measures built in to electronic health records, many will simply add these on to the one-size-fits-all panels of mostly unnecessary tests that they already do at routine physicals, increasing health care costs for little discernible benefit.

A recent JAMA editorial by former USPSTF member Steven Woolf, MD, MPH and current USPSTF-AAFP liaison Doug Campos-Outcalt, MD, MPA asserted that the Affordable Care Act's mandate for health insurers to provide first-dollar coverage of the Task Force's "A" and "B" recommended services has had the unintended (and unwelcome) effect of politicizing the panel's decisions:

Placing the USPSTF in this position puts its analytic rigor at risk by preventing members from concentrating on the science. The inescapable reality that their conclusions dictate coverage guidelines may engender a subliminal pressure to reinterpret the evidence, knowing the ramifications, and to lower the threshold for A and B recommendations. Although it was founded to offer guidance to clinicians, the USPSTF must now rethink its guidance, knowing that every word in its recommendations constitutes a statutory mandate. ... In the struggle between scientific truth and political influence, the latter often wins.

Although the USPSTF's change of heart on HCV screening makes a lot of sense when viewed through this lens, there is no way for an outsider to establish with confidence that pressure from other federal health agencies, private advocacy groups, or companies that make lucrative drugs for HCV unduly influenced its final recommendation statement. Regardless of the Task Force's particular motivations, abandoning risk factor assessment for HCV and HIV in favor of universal age-based testing is not justified by existing evidence and, perhaps more importantly, undermines the time-tested approaches of family medicine and primary care.

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