CHICAGO – Nearly one in seven patients in U.S. ambulatory cardiology practices who would have been recommended for initiation or intensification of antihypertensive drug therapy under the 2003 Seventh Joint National Committee guidelines are no longer treatment candidates under the 2014 expert panel recommendations.
These patients who no longer qualify for antihypertensive therapy under the 2014 guidelines turn out to have a disturbingly high average estimated 10-year risk of cardiovascular events. As a result, widespread adoption of the 2014 expert panel recommendations could have major adverse consequences for cardiovascular health, Dr. William B. Borden cautioned at the American Heart Association scientific sessions.
“Given the size and underlying cardiovascular risk of the population affected by the changes in the 2014 panel recommendations, close monitoring will be required to assess changes in practice patterns, blood pressure control, and – importantly – any changes in cardiovascular morbidity and mortality,” said Dr. Borden, a cardiologist at George Washington University in Washington.
Because the 2014 expert panel guidelines represent a major shift in hypertension management, Dr. Borden and coinvestigators sought to quantify the potential cardiovascular health impact of this more lenient treatment approach. For this purpose they turned to the National Cardiovascular Data Registry Practice Innovation and Clinical Excellence (NCDR PINNACLE) Registry, a voluntary quality improvement project involving outpatient cardiology practices.
Of 1,185,253 patients with hypertension as identified in their chart by a recorded diagnosis or notation of blood pressure greater than 140/90 mm Hg, 60% met the 2003 JNC 7 goals (JAMA 2003;289:2560-72), meaning the other 40% were candidates for initiation or intensification of antihypertensive therapy in order to achieve those goals (see chart). In contrast, 74% of hypertensive patients in U.S. cardiology practices met the less aggressive targets recommended in the 2014 expert panel report (JAMA 2014;311:502-20).
Thus, fewer than two-thirds of hypertensive patients in outpatient cardiology practices met the 2003 JNC 7 blood pressure targets, while three-quarters met the liberalized 2014 targets.
Dr. Borden and coworkers zeroed in on the 15% of hypertensive patients – that’s fully 173,519 individuals in cardiology practices participating in the PINNACLE Registry – who would have been eligible for treatment under the JNC 7 recommendations but not the 2014 expert panel guidelines. Interestingly, that 15% figure was closely similar to the 17% rate reported by Dr. Michael D. Miedema of the Minneapolis Heart Institute in an analysis of a more primary care population of older patients in the Atherosclerosis Risk in Communities (ARIC) study he presented in the same session.
Dr. William B. Borden
Dr. Borden and coinvestigators determined from medical records that the PINNACLE Registry group whose antihypertensive therapy treatment status changed between the two guidelines was at substantial baseline cardiovascular risk: Nearly two-thirds had been diagnosed with CAD, 54% had diabetes, 27% had a history of heart failure, 25% had a prior MI, and 23% had a prior transient ischemic attack or stroke.
This large group of patients who fell through the cracks between two conflicting sets of guidelines turned out to have a mean 10-year Framingham Risk Score of 8.5%. Upon incorporating the patients’ stroke risk using the atherosclerotic cardiovascular disease (ASCVD) risk score embedded in the 2013 ACC/AHA cholesterol management guidelines, their 10-year risk shot up to 28%.
The investigators then conducted a modeling exercise aimed at estimating the clinical impact of lowering systolic blood pressure in the elderly from about 150 mm Hg, as recommended in the 2014 expert panel guidelines, to about 140 mm Hg, as was the goal in JNC 7. To do so they extrapolated from the results of two randomized controlled clinical trials: the Systolic Hypertension in the Elderly Program (SHEP) and the Hypertension in the Very Elderly Trial (HYVET).
The result? Extrapolating from SHEP data, the 10-year ASCVD risk in these real-world elderly hypertensive patients caught between two conflicting sets of guidelines would drop from 28% to 19%. Using HYVET data, the average 10-year ASCVD risk would fall to 18.4%.
“This is equivalent to a number-needed-to-treat of 10-11 patients for 10 years in order to prevent one cardiovascular event,” according to Dr. Borden.
For the more than 80,000 patients over age 60 in the study population, that works out to roughly 8,000 cardiovascular events averted over the course of 10 years, he added.
The 2014 expert panel recommendations were based on a strict evidence-based review of published randomized controlled trials. The guidelines are new enough that it remains unclear if they will be embraced by clinicians or incorporated into performance measures and value-based health care purchasing programs.