SAN FRANCISCO — Unlike ACCORD, the ongoing SPRINT trial has every chance of showing an impact on cardiovascular outcomes with a blood pressure goal under 120 mm Hg, an investigator on both trials argued.
The large National Heart, Lung, and Blood Institute-sponsored SPRINT trial is comparing a goal of 120 versus 140 mm Hg in a broader population than included in the similarly-funded, diabetes-specific ACCORD trial.
No randomized trial has yet definitively proved or disproved a benefit in major clinical endpoints with any systolic goal under 150 mm Hg, William C. Cushman, MD, of the VA Medical Center in Memphis, Tenn., explained at the plenary session of the American Society of Hypertension meeting here.
“What you want from a trial like SPRINT and we wanted from ACCORD was to have such narrow confidence intervals that you exclude the possibility of significant benefit,” he told MedPage Today afterward. “You come up with a valid answer to say you should go there or you shouldn’t go there.”
The blood pressure portion of the ACCORD trial yielded a nonsignificant 12% lower risk of the primary outcome of nonfatal MI, nonfatal stroke, and death from cardiovascular causes, which Cushman reported in a double-whammy session at the 2010 American College of Cardiology meeting along with the negative findings for intensive lipid lowering.
But the wide confidence intervals included anywhere from a 27% benefit to a 6% harm from intensive blood pressure management to a goal of 120 mm Hg.
And the trial was “unexpectedly underpowered, probably at least in part because several high-risk populations — including most chronic kidney disease patients and those 80 and older — were excluded,” Cushman noted.
SPRINT took lessons from the ACCORD subgroup analyses in diabetes, as patients with better controlled glucose levels tended to benefit from intensive management whereas those with a hemoglobin A1c of 8% or higher didn’t and the stroke reduction with the lower blood pressure target was greater in those 65 and older.
The new trial includes more than 9,000 hypertensive patients without diabetes but at high risk because of one or more of the following:
- Clinical or subclinical cardiovascular disease other than stroke
- Chronic kidney disease with an estimated glomerular filtration rate of 20 to 59 ml/min/1.73 m2
- A Framingham risk score of 15% or higher for 10-year cardiovascular risk
- Age 75 or older
Primary results — a composite endpoint slightly different from ACCORD in inclusion of heart failure and acute coronary syndrome — were theoretically due in 2016, but that date could be pushed back as far as 2018 because recruitment started later than planned.
“If SPRINT shows benefit it may say maybe these older studies — ACCORD, MDRD, AASK, whatever — weren’t big enough or powerful enough,” Cushman noted.
A definitive positive answer for the 120 mm Hg goal would stand to double the population of patients treated for hypertension in the U.S., he pointed out.
But a negative answer would be important for practice, too, he told MedPage Today in an interview.
“There are a lot of people who assume because the epidemiology shows lower to be better … in practice, people, while knowing that we weren’t recommending that [in JNC7], still often use 120 as the goal because it’s a ‘normal’ value,” he said.
Source: MedPage Today.
