New hypertension guidelines: What’s changed and why
The lower threshold for hypertension diagnosis in the 2017 ACC/AHA* hypertension guidelines does not necessarily entail more pharmacological treatment, says a leading expert in cardiology during a presentation at AFCC 2018, who highlights that the first key step for managing hypertension is lifestyle modification.
Also, with the recent release of the 2018 ESC/ESH** guidelines for hypertension, physicians should look for the common threads that bind the international guidelines when faced with a case in whom recommendations from different guidelines are conflicting, he urged.
Lower threshold ≠ more drugs
Unlike the previous blood pressure (BP) threshold of 140-159/90-99 mm Hg for stage 1 hypertension in JNC7, the new threshold has now been lowered to 130-139/80-89 mm Hg in the 2017 ACC/AHA guidelines — essentially elevating what used to be defined as prehypertension to stage 1 hypertension.
“When these guidelines were published, there was a great deal of concern raised that relate to the number of individuals being diagnosed with hypertension and the number of those requiring drug therapy,” said Dr Andrew Kates, Professor of Medicine from Washington University School of Medicine, St Louis, Missouri, US.
Compared with JNC7 recommendations, the ACC/AHA guidelines substantially raised the prevalence of hypertension in the US population by 13 percent, from 32 percent to 45 percent of US adults who met the diagnosis criteria for hypertension. Nonetheless, the increase in the proportion of adults recommended for antihypertensive medications was small, from 34.3 percent based on JNC7 to 36.2 percent according to ACC/AHA criteria. [J Am Coll Cardiol 2018;71:109-118]
“The reason why although the percentage diagnosed with hypertension increases markedly, the absolute number requiring treatment is quite similar is because … for many newly diagnosed hypertensives [based on the ACC/AHA guidelines], the first step of treatment isn’t necessarily pharmacological therapy, but more importantly, nonpharmacological strategy,” said Kates.
“For those with elevated BP, stage 1, or even stage 2 hypertension, nonpharmacological strategy promoting optimal lifestyle habit really is the key first step in treatment [based on the ACC/AHA guidelines],” he stressed, pointing out that interventions involving weight loss, healthy diet, reduced intake of dietary sodium, and increased intake of dietary potassium have important effects on reducing BP.
No one drug better than other in first line
The next step before initiating pharmacological therapy is to consider a patient’s risk — the presence of ASCVD*** or 10-year CVD risk ≥10 percent. Where antihypertensive medications are indicated, the first-line agents recommended in the ACC/AHA guidelines include ACE inhibitors or ARBs, CCBs#, and thiazide diuretics, with “no one drug being better than the other, unless there is compelling indication for another specific agent,” said Kates.
For patient subgroups comorbid with compelling indications, for example, those with ischaemic heart disease, valvular heart disease, aortic disease, heart failure, chronic kidney disease (CKD), or diabetes, personalizing pharmacological therapy is essential.
“The choice of drug class is important for patients who have compelling indications related to underlying disorders,” he stated.
Monotherapy vs combination therapy
While monotherapy is considered "reasonable" for stage 1 hypertension in the ACC/AHA guidelines, the ESC/ESH 2018 guidelines recommend a two-drug combination pill — combining an ACE inhibitor/ARB with a CCB /diuretic — as initial treatment for patients with uncomplicated hypertension.
“One of the rationale behind why two drugs are better than one relates to the additive effects of two agents,” said Kates. “Combining antihypertensive drug classes has been shown to be about fivefold more effective for lowering BP than doubling the dose for one drug.” [Am J Med 2009;122:290-300]
In face of conflicts
Unlike the ACC/AHA guidelines which classify SBP of 130-139 mm Hg as stage 1 hypertension, this range is considered “high-normal” in the ESC/ESH 2018 guidelines, which define grade 1 hypertension at an SBP range of 140-159 mm Hg.
The difference in diagnosis threshold between guidelines, however, poses challenge to physicians, according to Kates, who drew a case example of a 63-year-old female patient presenting with a BP reading of 148/86 mm Hg.
“When it comes to someone like this with somewhat conflicting recommendations, looking for common threads [from the major guidelines] is key,” advised Kates, referring to common threads in SBP target, definition of high risk that indicates change to lower BP target, and definition of how low is too low for BP target.
Summing up, the common threads that bind the major international guidelines allude to a minimum SBP treatment goal of <150 mm Hg for most individuals, <140 mm Hg for high-risk patients; taking into account risk such as diabetes, clinical/subclinical CVD/coronary artery disease, CKD, and future CVD risk for BP targets and treatment decisions; and keeping in mind that there is risk in lowering BP beyond a certain point (the J-curve). [J Am Coll Cardiol 2018;72:1246-1251]