AHA: SPRINT’s results upend hypertension targets

ORLANDO – Results from the SPRINT hypertension trial had been highly anticipated ever since the study stopped early in August and the sponsoring National Heart, Lung, and Blood Institute released the top-line positive result in September that treating systolic blood pressure to a target of less than 120 mm Hg led to statistically significant drops in a composite of cardiovascular endpoints as well as in all-cause death, compared with the standard target of less than 140 mm Hg.

When the much fuller report on the results finally came out in a special session at the American Heart Association scientific sessions as well as in a simultaneous publication (N Engl J Med. 2015 Nov 9. doi: 10.1056/NEJMoa1511939), the data left attendees buzzing and debating what the results will mean for revised hypertension guidelines and for clinical practice.

The most prominent reactions were accolades for the trial, starting with the independent discussants that the AHA invited to comment at the session, an outpouring of praise reminiscent of that showered on a hit movie:

“A major coup. Thank you, NHLBI,” declared Dr. Marc A. Pfeffer, professor of medicine at Harvard and a cardiologist at Brigham and Women’s Hospital in Boston.

“Thank you for this groundbreaking study,” said Dr. Clive Rosendorff, professor and cardiologist at Mount Sinai Hospital in New York.

^{Mitchel L. Zoler/Frontline Medical News}

Dr. Daniel W. Jones

“A remarkable trial. The most important blood pressure study in the last 40 years,” gushed Dr. Daniel W. Jones, professor of medicine at the University of Mississippi, Oxford, and director of clinical and population sciences at the Mississippi Center for Obesity Research, Jackson.

Following the huzzahs came a more substantive discussion among meeting attendees of what results from the 9,361-patient Systolic Blood Pressure Intervention Trial will mean for revised blood pressure goals in U.S. guidelines, what it might mean for defining who has hypertension, and how it might influence practice. Perhaps the most pressing issue for the AHA and American College of Cardiology panel that began work on a new revision of hypertension treatment guidelines earlier this year is how to reconcile the SPRINT results with finding from prior studies, especially the 2010 report of results from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial (N Engl J Med. 2010;362[17]:1575-85.).

ACCORD, at half the size of SPRINT with 4,733 patients, had a very similar design as SPRINT but included only patients with diabetes while SPRINT excluded patients with diabetes. ACCORD failed to show a significant difference in its primary composite outcome after an average of 4.7 years between patients randomized to a hypertension treatment target of less than 140 mm Hg or less than 120 mm Hg, the same goals as in SPRINT. ACCORD did show a statistically significant 41% relative risk reduction for stroke, also in contrast to SPRINT, which showed a much less robust and nonsignificant 11% relative risk reduction in stroke.

In his commentary on SPRINT, Dr. Jones offered several possible explanations for the divergent results, including a possible inherent difference in vascular physiology between patients with diabetes and those with normal glycemic control; the younger patients enrolled in ACCORD (patients averaged 62 years old in ACCORD and 68 years old in SPRINT, and 28% of patients in SPRINT were at least 75 years old); the use of hydrochlorothiazide as the predominant diuretic in ACCORD versus predominant use of chlorthalidone in SPRINT; and the multiple interventions simultaneously tested in ACCORD, which also randomized patients into two arms with respect to glycemic control and into two arms of different lipid-controlling treatment.

Dr. Salim Yusuf

SPRINT’s results “need to be assessed in the context of ACCORD,” commented Dr. Salim Yusuf in an interview. “I think the real result is somewhere in between the results of SPRINT and ACCORD” in terms of the appropriate systolic blood pressure target. What we need is a balanced perspective that takes all the trials. SPRINT was a very good trial, but like all studies it should be interpreted in the context of all the other related studies, not in isolation,” said Dr. Yusuf, professor and director of the Population Health Research Institute of McMaster University in Hamilton, Ont.

“Understandably, when something like SPRINT comes out there is a lot of enthusiasm. The first reaction is always ‘Wow!’ For patients who meet SPRINT’s enrollment criteria I think we will treat to a target of less than 120 mm Hg. But the guideline writers need to discuss SPRINT and balance it,” he said.

Despite his regard for SPRINT, Dr. Yusuf cited several additional concerns he has about the trial: