Are Clinical Practice Guidelines More Contentious Than Ever?

Tricia Ward


June 14, 2018

The latest American College of Cardiology (ACC)/American Heart Association (AHA) blood pressure guidelines.[1] are not the first practice guidelines to spark debate. The AHA took a mulligan and rescinded sections of the recent stroke guidelines[2] after feedback from the stroke community; meanwhile, primary care associations have pushed back against specialty organization recommendations in various clinical areas. Are clinical practice guidelines more contentious than ever, or is it the same as it ever was?

Physicians have never taken kindly to being told how to practice medicine. In 1912, none other than William Osler bemoaned that knowledge of high blood pressure had "filtered to the laity with the usual disastrous results. A good many people are unnecessarily alarmed, and much needless worry and anxiety has been caused."[3] One can only imagine what Osler would make of the targets in the latest ACC/AHA blood pressure guidelines that render almost one half the adult US population hypertensive.[1]

The First US Guidelines

The American College of Surgeons boasts that it has set the quality standard for more than 100 years, which includes issuing the first formal US guidelines in 1931 on fracture care.[4]

The first cardiology guidelines were a collaboration of the AHA and the Cardiac Society of Great Britain and Ireland on a joint standard for blood pressure measurement. "The reader may feel that such recommendations are not needed and that everyone knows how to take blood pressure and does it the same way. The committee have learnt that this is not the case," the authors wrote in 1939.[5]

Almost 70 years later, in an interview about the ACC/AHA blood pressure guidelines—which include specific instructions on how to take blood pressure—Paul Whelton, MD, lamented that "[w]e wouldn't fly in a plane if a captain didn't follow the recommendations for what she or he has to do before flying. Yet, we've tolerated poor measurements of blood pressure."

Proliferation of Guidelines

A search of library catalogs by Canadian writers found 35 guidelines published between 1960 and 1974, mostly from the United States and Britain.[6] As of June 2018, the National Guideline Clearinghouse (NGC) lists 1360 guideline summaries, including 140 in cardiology.

The proliferation of clinical practice guidelines over the past few decades is tied to observations of geographic variations in procedure rates.[7] A 1987 paper in JAMA investigating such variation in the use of three procedures, including coronary angiography and carotid endarterectomy, deemed 32% of the carotid interventions inappropriate.[8] It was assumed that guidelines would reduce practice variation and inappropriate use.

Shortly thereafter, the Omnibus Budget Reconciliation Act of 1989  created the Agency for Health Care Policy and Research (AHCPR) to focus on outcomes and effectiveness research and address concerns with "ceaselessly escalating healthcare costs, wide variations in medical practice patterns, evidence that some health services are of little or no value, and claims that various kinds of financial, educational, and organizational incentives can reduce inappropriate utilization"[9]

In 1994, the AHCPR was the target of the North American Spine Society's ire after it supported research and issued a report concluding that spinal fusion surgery is often ineffective.[10] One of the society's board members went as far as founding an advocacy group with the aim of eliminating funding for the AHCPR.[11] The agency, now rebranded as the Agency for Healthcare Research and Quality (AHRQ), survived the attack but is perennially under threat of defunding (although it may escape the most recent National Institutes of Health (NIH) budget cuts).

The Role of the NIH and NHLBI

In 1977, the National Heart, Lung, and Blood Institute (NHLBI) released the first clinical practice guideline from the National High Blood Pressure Education Program.[12] The first report of the National Cholesterol Education Program came out over 10 years later.[13] Periodic releases from these expert panels were the prevailing guidelines for hypertension and lipid management for several years.

In 2013, as the medical community awaited updates to five cardiovascular guidelines (cholesterol, blood pressure, risk assessment, lifestyle interventions, and obesity), the NHLBI announced that it would step away from the guideline-writing business, conceding that "numerous organizations outside government have developed expertise and experience in developing guidelines."[14]

The five NHLBI guideline working groups had completed evidence reviews and were invited to collaborate with the professional societies to prepare the final documents; notably, the hypertension writing panel declined to do so. By November 2013, four new cardiovascular guidelines were released simultaneously. Shortly thereafter, not one but three competing guidelines on hypertension were released in quick succession. Even more followed.

Any hopes that the 2017 AHA/ACC blood pressure guidelines might resolve the conflicts have not been realized.

A Timeline of Adult Blood Pressure Targets in the United States (2003-2017)

What is the NHLBI's current role in guidelines? George A. Mensah, MD, director of the Center for Translation Research and Implementation Science of the NHLBI, responded by email that "[i]n alignment with the IOM [Institute of Medicine] standards and other NIH Institutes, the NHLBI continues to support rigorous evidence reviews and enables collaborative partners to construct clinical practice guidelines important to public health."

When asked about the seeming increase in conflicting guidelines since the 2013 role change, Mensah responded that "we recognize that when we fund trials, there will be uncertainties both pending the results of trials and even on how to interpret their outcomes once they are completed and reported. Thus, as a research agency, we rely on those closest to clinical practice to help address these medical opinions and perspectives." This was probably a reference to criticisms from the American Academy of Family Physicians and the American College of Physicians that the NIH-funded SPRINT trial was given too much weight in the ACC/AHA blood pressure guidelines.

Quality Standards

Several organizations, including the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group, have set quality standards for guidelines and their evidence base. The IOM issued its first report on clinical practice guidelines in 1990.[15] Over 20 years later, the IOM publication Clinical Practice Guidelines We Can Trust proposed eight standards for developing trustworthy clinical practice guidelines (Table), noting that "many current clinical practice guidelines suffer from limitations in the scientific evidence base and shortcomings in the guideline development process."[16]

Indeed, an analysis of a random sample of 130 clinical practice guidelines archived on the NGC website in June 2011 found that fewer than one half met more than 50% of the IOM standards.[17]

Table. Institute of Medicine Standards for Trustworthy Guidelines[16]
Establishing transparency
Management of conflict of interest
Guideline development group composition
Clinical practice guideline/systematic review intersection
Establishing evidence foundations for and rating strength of recommendations
Articulation of recommendations
External review

One point of contention is whether clinical practice guidelines should include expert opinion on clinical questions with a weak evidence base.

An analysis of ACC/AHA practice guidelines issued from 1984 to September 2008 found that only 245 of the 1305 class I recommendations had an A level of evidence.[18] A subsequent analysis found that 1 out of 5 class I recommendations in 11 ACC/AHA clinical practice guidelines published between 1998 and 2007 did not appear in the subsequent guideline.[19] Just under 10% of the more than 600 class I recommendations reviewed were downgraded or reversed; recommendations based on consensus opinion were the most likely to be omitted, downgraded, or reversed.

Limiting recommendations to those supported by a high level of evidence is no guarantee of avoiding controversy. The 2013 ACC/AHA cholesterol guidelines[20] caused a furore over the abandonment of low-density lipoprotein cholesterol (LDL-C) targets and the embrace of a new atherosclerotic cardiovascular disease (ASCVD) risk calculator. The cholesterol expert panel's defense was that adhering strictly to the IOM standards for evidence reviews[21] limited the evaluation to randomized controlled trials (RCTs) with ASCVD outcomes and systematic reviews and meta-analyses of such RCTs. They were unable to find RCT evidence to support the continued use of specific LDL-C and/or non–high-density lipoprotein cholesterol treatment targets. The writers acknowledged that "future clinical trials may provide information warranting reconsideration of this strategy."

Currently, there are 34 cardiology guidelines that touch upon cholesterol management listed on the NGC website; many, including those from the National Lipid Association,[22] advocate treating to LDL-C targets based on expert opinion. An updated ACC/AHA lipid guideline is scheduled for release before the end of 2018.

Adherence to Guidelines as Quality Metric

A Milbank Quarterly review[6] on the emergence of clinical practice guidelines notes that "[d]epending on the circumstances, guidelines may protect against criticism, legal action (if followed), or efforts to contain costs, or they may promote all of these" [our emphasis].

The use of practice guidelines by payers and regulators to reward (or punish) is one reason cited for increasing discrepancies between specialist and general-practice guidelines.

Despite warnings about "cookbook" medicine, clinical practice guidelines have been shown to improve quality of care[23,24]; however, some question "whether they achieve this in daily practice."[25]

As a recent editorial in the Annals of Internal Medicine about conflicting guidelines on glycemic targets for patients with diabetes put it, "Although the development of simple, straightforward, universally applied guidelines is appealing, the reality is that many clinical situations are complex and patients' needs are unique.... Recommendations will never be evidence-based at the individual-patient level."[26]

It is noteworthy that the final sentence of the summary text of the ACC/AHA blood pressure clinical practice guideline reads, "This document is, as its name implies, a guide. In managing patients, the responsible clinician's judgment remains paramount."[1]

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