Is an ounce of detection worth a pound of public health prevention?

It is a rare occasion nowadays when academic journals treat us to an editorial debate of some substance.  The staff at the Journal of the American College of Cardiology can be applauded for publishing last summer two articles representing fundamentally opposed viewpoints on the best strategy to avoid cardiovascular illness.  Amusingly, both claimed in the title of their piece the distinction of promoting a “rational approach” for the reduction of cardiovascular risk.

On the right, Drs. Jay Cohn and Daniel Duprez proposed screening for early disease, fashioning their method on the model of cancer detection.  Their approach consists of applying a battery of non-invasive tests to look for the presence of cardiovascular abnormalities: the 12-lead electrocardiogram, tests of large and small artery elasticity, measurements of the resting blood pressure and of its response to a moderate exercise, optic fundus photography, ultrasonography for left ventricular mass and volume and for carotid intima-media thickness, detection of microalbuminuria, and determination of blood N-terminal pro-B-type natriuretic peptide level.  The results on the tests lead to the formulation of a composite score, named the Rasmussen score, which presumably reflects the burden of early disease and can prompt a decision to recommend “aggressive intervention.”

Their opinion piece is an overt challenge to current dogma focused on risk factor modification:

The problem with the message to prevent and treat risk factors is that it may be good public health policy but does not translate into a useful strategy for individual patient care.

Adding,

Does a 20% or 30% higher risk in one patient justify an intervention that is not to be used in the patient without such an increased risk?  That seems to be a remarkably crude and imprecise approach to decision making. Risk factors are not the disease.

Of course, there is also no reason why a low Rasmussen score could not trigger a decision to avoid treating risk factors, but Cohn and Duprez wisely side-stepped addressing this possible use of their proposed algorithm lest they be accused of heretical therapeutic nihilism.

As it was, the response from the left was swift.  In their editorial retort, Drs. Philip Greenland and Donald Lloyd-Jones deemed the screening porposal “superficially attractive,” but warned that such an approach does not satisfy “essential criteria” for screening established by the World Health Organization and the United States Preventive Services Task Force, evidently citing the high courts of clinical decision-making.  The substance of their rebuttal rested on drawing a parallel between Cohn and Duprez’s proposal and the experience with coronary artery calcium scoring.  They provided a detailed and correct analysis of why calcium scoring failed as a useful clinical tool but used this one example to quickly generalize against any approach at early detection, invoking the familiar but all too specious arguments about the lack of “cost-effectiveness or outcomes data” and the potential “harm of screening” that may either provide “false reassurance” or else lead to “considerable added medical expense and invasive procedures.”  They did not leave any room for negotiation:

In our judgment, additional studies of screening strategies, including patient outcomes, are needed before recommending any form of routine CVD screening for the asymptomatic patient.

And,

In conclusion, we agree with the USPSTF that the best approach at this time for CVD assessment and prevention lies in routine testing for traditional coronary risk factors.

This is a disingenuous defense of the traditional risk factor approach.  Our public health officials have measured the prevalence of hypertension to be 30% of the US adult population and about 50% of middle-aged Americans.  Adding to this the other ubiquitous risk factors and taking into account the bold new concepts of “pre-hypertension,” “pre-diabetes,” and the ratcheting down of the “normal” cholesterol level, and pretty soon any hapless individual over 50 is certifiably “at risk.”   Decades of vigorous “public awareness” campaigns and sloppy teaching of medical students and residents have, for all practical purpose, obliterated any notion that “risk factors are not the disease,”  subjecting anyone so labeled to never-ending (and mostly hypocritical) admonishments for “lifestyle changes” and to a lifetime of pharmacologic dependence.  Yet the most likely immediate risk such factors seem to confer is that of receiving a healthy dose of radioactive thallium for reporting a mere hiccup to a zealous health care provider eager to conform to the expected standard of care.  As for outcomes or cost-effectiveness, public health policy can only resort to propaganda and hubris to justify its purported success.

I do not know if Cohn and Duprez’s particular combination of laboratory tests and Rasmussen score is optimal for the detection of cardiovascular disease.  I do applaud them for including optic fundus photography.  Of the tests of arterial elasticity, I share Greenland and Lloyd-Jones’ reservations regarding the maturity of the technology.  They are also correct in questioning the reliability of carotid IMT assessment, at least in its current form.  But does this justify a barrage of unrealistic objections driven primarily by a peculiar philosophy of what medicine is all about?  Had Laennec been asked for “additional studies” to justify the use of the stethoscope, health care would be sadly different today.

It is a distressing reflection on the sclerosis of our “system” that Cohn and Duprez must draw the same conclusion as their opponents’ and plead that “clinical trials to document the cost effectiveness of this [early detection] approach are urgently needed.”  That is only true by virtue of our essentially socialized health care system in which the only way forward is through the rigid channels of population medicine: clinical trials and expert committee opinion now essential to gain favor among the powers that be and obtain from them the grace of a FDA approval or a CPT code.

In a Utopian medical environment free from politico-financial restrictions, such a requirement would be wholly unnecessary.  Instead of applying their means of persuasion to a national audience of “opinion leaders,” Cohn and Duprez would need to first convince their immediate colleagues and the general public in their vicinity of the value of their screening strategy.  Through normal market mechanisms, the price of the procedure would reflect the aggregate intensity of interest in early detection from among the public and the referring physicians.  Should the interest be great, entrepreneurial competition would attract others into the field who would refine the procedure and reduce its price over time, in the same way that competition improves the quality and decreases the price of cellular phones and personal computers.  Should the interest be scant, we might see the Rasmussen score go the way of cardiac ballistography into the graveyard of promising but ineffectual technologies.

But as it is, the Rasmussen battery is unlikely to find its deserved place in the armamentarium of medical tools.  For even if a clinical trial did demonstrate the “cost-effectiveness” of the Rasmussen score, this would simply sanction the method as another tool of population medicine to be indiscriminately promoted to the public at large.  The method may qualify for reimbursement but its price would be established by the byzantine and political process that currently determines the monetary worth of medical services and procedures.

The more likely fate for the Rasmussen score, however, is that it will continue to face the firm disapproval of a public health establishment determined to obstruct any challenge to the claim that the best course of action to deal with the perils of life must necessarily be entrusted to the enlightened elites.