Are the JNC-8 Guidelines for High Blood Pressure Misguided?
Elevated blood pressure is the leading cause of death globally1 and the most common cardiovascular risk factor in older persons. The recent release of the 2014 Evidence-Based Guidelines for the Management of High Blood Pressure in Adults2 represents a bold step, presenting treatment guidelines based nearly entirely on systematic reviews of multicenter randomized clinical trials. These guidelines used the strength of recommendation grading system developed by the National Heart Lung and Blood Institute Evidence-Based Methodology Lead. The evidence review focused on 3 key questions: 1) in adults with hypertension, does initiating antihypertensive pharmacologic therapy and specific blood pressure (BP) thresholds improve health outcomes?, 2) In adults with hypertension, does treatment with antihypertensive pharmacologic therapy to a specific BP goal lead to improvements in health outcomes, and 3) In adults with hypertension, do various antihypertensive drugs or drug classes differ in comparative benefits and harms on specific health outcomes? The authors are to be commended for the rigor of the scientific approach used to evaluate the evidence, as well as the transparent protocol followed to formulate the recommendations presented in the report.
Only two "strong Grade A" recommendations were made in the guideline. The first and perhaps most controversial was the move to raise the threshold for initiating pharmacologic therapy in those aged 60 years and older to a systolic blood pressure of 150 mmHg, aiming to treat to a goal below 150 mmHg (instead of 140 mmHg in JNC-7). While it has been well over a decade since clinicians have been asked to treat patients to a goal of <140/90 mmHg, many patients still do not reach this target. With less stringent efforts from a higher target of 150 mmHg, many more will have their systolic BP hovering around or above 150, particularly in older persons with comorbidities where isolated systolic hypertension is the most common subtype of hypertension and systolic blood pressure typically averages 20 mmHg or more from goal3. As a large meta-analysis of clinical trials has shown a reduction of even 10 mmHg of systolic blood pressure to result in a 22% reduction in CHD events and 41% reduction in stroke4, one may speculate whether the new approach of a higher BP initiation and target goal in those aged 60 and older (where most such events occur) could ultimately result in greater burden to society from corresponding increases in healthcare costs for acute events. Some solace to this is a "corollary recommendation", although graded E for expert opinion, noting that if treatment does result in a lower achieved blood pressure of <140/90 mmHg without undue burden from side effects, that treatment "does not need to be adjusted."
The other Grade A recommendation, keeping younger persons (aged 30-59) treated to a diastolic BP of <90 mmHg, will probably not create much argument; however, in these younger persons, a recommendation of a BP initiation level of 140/90 mmHg and goal below this point was graded only E for expert opinion. It was felt there was insufficient evidence for a systolic goal for those aged 30-59 or a diastolic goal in those under age 30. Moreover, consistent with recent European Society of Hypertension and American Diabetes Association recommendations, the initiation level for treatment in those with diabetes was increased to >=140 mmHg systolic, but inconsistent was raising the diastolic goal from <80mmHg to <90 mmHg. Not discussed were earlier recommendations promoting the use of home and ambulatory blood pressure readings, as reliance on clinic blood pressures results in misclassification due to persons with masked and white coat hypertension. And such misclassification (e.g., prevalence of masked hypertension) appears to be even greater in those with diabetes.
It is likely that clinicians will find the age-criterion for recommending different treatment initiation levels, and the abandonment of BP goals in other age groups, to be confusing.Most would probably agree there is nothing magical about crossing the age threshold that warrants a different approach (e.g., are those aged 61 vs. 59 really different?). And despite realizing side effect profiles and risk of falls are greater in older persons (potentially some reasons to validate the change in target in this group), what is not addressed is that these persons are at substantially higher absolute risk for cardiovascular events than younger persons. Ideally treatment initiation and intensification should be based more on the patient's global risk, a concept that has been established for over 15 years5 and in fact recently recommended by the new AHA/ACC blood cholesterol treatment guidelines6. These new guidelines were bold in recommending statin therapy to four major risk groups, three of which were irrespective of LDL-C levels. Perhaps treatment of hypertension should also take this direction. Or even more appropriate would be comprehensive risk factor management (as opposed to individual treatment of BP, lipids, diabetes, etc.) according to a patient's global risk.
While the authors maintain that "these recommendations are not a substitute for clinical judgment", guidelines like these — and how they are interpreted in the press and elsewhere — ultimately have the effect of modifying healthcare from organizational performance targets to individual physician and patient practices. Importantly, they should also ultimately have the effect of improving patient outcomes. However, whether this will be the case here is uncertain.
Moving forward, it will be an important priority of organizations such as the ACC and AHA together with primary care and other specialty organizations to help foster an integrated guideline implementation approach that better ties together in a harmonious fashion the practical application of the risk assessment, lifestyle, obesity, cholesterol, and now the hypertension guidelines.
- Global Atlas on Cardiovascular Disease Prevention and Control. Mendis S, Puska P, Norrving B editors. World Health Organization, Geneva 2011.
- James PA, Oparil S, Carter BL, et al. 2014 Evidence-Based Guideline for the Management of High Blood Pressure in Adults. Report from the Panel Members Appointed to the Eighth Joint National Committee (JNC8). JAMA 2013 (epub ahead of print).
- Wong ND, Lopez VA, L'Italien G, Chen R, Kline S, Franklin SS. Inadequate control of hypertension in U.S. adults with cardiovascular disease comorbidities in 2003-2004. Arch Intern Med 2007; 167 (22): 2437-42.
- Law MR, Morris JK, Wald NJ. Use of blood pressure lowering drugs in the prevention of cardiovascular disease: meta-analysis of 147 randomised trials in the context of expectations from prospective epidemiological studies. BMJ. 2009;338:b1665
- Califf RM, Armstrong PW, Carver JR, D'Agostino RB, Strauss WE. 27th Bethesda Conference: matching the intensity of risk factor management with the hazard for coronary disease events. Task force Stratification of patients into high, medium and low risk subgroups for purposes of risk factor management. J Am Coll Cardiol 1996; 27: 1007-1019.
- Stone NJ, Robinson J, Lichtenstein AH, et al. 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; S0735-1097. Epub ahead of print.
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