One of my residents presented some research that she had completed under my supervision. Since I left the staff of the U.S. Preventive Services Task Force four years ago, it has been my sense that the Task Force has substantially lowered its evidence “bar” for recommending a preventive service, an impression confirmed in private discussions with colleagues who closely follow the group’s activities. In a JAMA editorial published last year, Drs. Steven Woolf and Doug Campos-Outcalt expressed concerns that the Affordable Care Act, by requiring insurers to fully pay for grade “A” and “B” recommended services, would lead to political pressure on the USPSTF to produce more of these favorable recommendations.

My resident and I hypothesized that if this concern turned out to be correct, we would find that a higher proportion of recommendation statements — both new and updated — published in 2011 or later would be grade “A” or “B” rather than “C,” “D,” or “I.” After reviewing the Task Force’s portfolio of active recommendations, she concluded that this is absolutely the case. Of course, not being able to attend the meetings or review their minutes (that are unavailable to the public), we could only demonstrate an association, not causation. Another plausible explanation is that research progress over the past several years has produced more evidence and effective interventions to support providing services that weren’t recommended before (e.g., lung cancer screening with CT scans, screening for hepatitis C). That’s unlikely to be the whole story, though, since the TF would have generated more new “D” (don’t do it) recommendations too, which hasn’t happened.

Politics aside, the other problem with linking USPSTF decisions to “free” preventive services is that a group that adamantly does not consider cost in assessing the value of a preventive service increases the cost of health care (and health insurance premiums) every time it makes a favorable decision. Dr. Woolf has argued that effective prevention doesn’t have to be cost-saving, only cost-effective, and the vast majority of immunizations and recommended screenings meet this criterion. Even CT screening for lung cancer, according to a recent study, would cost $81,000 per quality-adjusted life year (QALY) gained if appropriately implemented in a high-risk population similar to that in the National Lung Screening Trial.

But cost-effective services can still end up being terrifically expensive. If the estimated 9 million eligible Americans receive “free” annual low-dose CT scans recommended by the USPSTF at $300 per scan, that’s $2.7 billion added to the national health care bill each year — and this doesn’t count the costs of all of the follow-up CT scans for abnormalities, consultations, biopsies, and treatments that will ensue. If birth cohort screening finds 2 million previously unidentified adults with hepatitis C who subsequently take the new drug sofosbuvir (Sovaldi) at $84,000 per treatment course, it will cost $168 billion to pay for this drug alone, not counting other medications or costs of care.

Even if paying for these screening tests will ultimately provide health benefits to many (though I have qualms about the evidence for both), they will also make health insurance premiums a little less affordable, and it’s nobody’s job to decide if the benefits are worth the added costs. In an article in Health Affairs, Dr. Mark Pauly and colleagues argue that complete pooling of risk is justifiable only for preventive services that are highly cost-effective. They propose continuing full coverage for the most cost-effective services, increasing patient cost-sharing for less cost-effective services, and discouraging coverage of services that are not cost-effective according to a societally-determined threshold (they suggest $400,000 per QALY).

Plenty of public health and health equity arguments that could be made against this proposal, but what I like about it is that it sees the forest for the trees. Not matter how equally we distribute them (and the U.S. does a poorer job at this than most countries), health care resources are limited, and money spent on marginally effective services is money that’s not being spent on countless other things that promote health and make life worth living. It’s simply not enough to prioritize evidence-based preventive care by making all of it “free,” regardless of the true costs.

Kenneth Lin is a family physician who blogs at Common Sense Family Doctor.  This article originally appeared in the AFP Community Blog.