The findings were released by JAMA. In a divisive move, the Eighth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 8), relaxed the blood pressure goal in adults aged 60 years and older to 150/90 mm Hg, instead of the previous goal of 140/90 mm Hg.
Blood pressure goals were also eased for adults with diabetes and kidney disease.
“Raising the target in older adults is controversial, and not all experts agree with this new recommendation,” said lead author Ann Marie Navar-Boggan, MD, Duke University School of Medicine, Durham, North Carolina. “In this study, we wanted to determine the number of adults affected by these changes.”
The researchers used data from the National Health and Nutrition Examination Survey (2005-2010), conducted by the Centers for Disease Control and Prevention (CDC), to examine blood pressure measurements of more than 16,000 participants.
Based on the study sample, the researchers determined that the proportion of US adults considered eligible for hypertension treatment would decrease from 40.6% under the old guidelines to 31.7% under the new recommendations.
In addition, 13.5 million adults -- most of them aged older than 60 years -- would no longer be classified in a danger zone of poorly controlled blood pressure, and instead would be considered adequately managed. This includes 5.8 million US adults who would no longer need blood pressure medications if the guidelines were rigidly applied.
“The new guidelines do not address whether these adults should still be considered as having hypertension,” said Dr. Navar-Boggan. “But they would no longer need medication to lower their blood pressure.”
According to the study, 1 in 4 adults aged older than 60 are currently being treated for high blood pressure and meeting the stricter targets set by previous guidelines (JNC 7).
“These adults would be eligible for less intensive blood pressure medication under the new guidelines, particularly if they were experiencing side effects,” said Dr. Navar-Boggan. “But many experts fear that increasing blood pressure levels in these adults could be harmful.”
He added that even under the newer, less stringent guidelines, an estimated 28 million US adults with hypertension still have uncontrolled blood pressure, and over half of them remain untreated.
“Uncontrolled hypertension is a huge missed opportunity for prevention of cardiovascular diseases such as stroke and heart attack,” he said.
In an accompanying JAMA editorial, Harlan M. Krumholz, MD, Yale University School of Medicine, New Haven, Connecticut, noted that these new guidelines, with their innovations and controversy, have established a new course.
“Navigating it may be uncomfortable and will perhaps force clinicians to grapple with issues that have been ignored for too long,” he wrote. “While it is important to advocate for health and promote healthy environments and behaviours on the broader scale, for medical decision making, it is even more important to ensure informed choice with the full participation of the person who will incur the risks and benefits of the decision. When viewed through this lens, the controversies about the guidelines become less contentious and the focus shifts to refining the evidence and producing better ways to communicate what is known for decision-making purposes. By directing attention to that message, already firmly embedded in these guidelines with their bold recommendations and deference to patient preference, they may have accomplished more than they ever envisioned.”