AT THE AHA SCIENTIFIC SESSIONS
ANAHEIM (FRONTLINE MEDICAL NEWS) – If blood pressure isn’t measured the way it was in the SPRINT trial, it shouldn’t be treated all the way down to the SPRINT target of less than 120 mm Hg; it’s best to aim a little higher, according to investigators from Kaiser Permanente of Northern California.
SPRINT (the Systolic Blood Pressure Intervention Trial) found that treating hypertension to below 120 mm Hg – as opposed to below 140 mm Hg – reduced the risk of cardiovascular events and death, but blood pressure wasn’t measured the way it usually is in standard practice. Among other differences, SPRINT subjects rested for 5 minutes beforehand, sometimes unobserved, and then three automated measurements were taken and averaged ( N Engl J Med. 2015 Nov 26;373:2103-16 ).
But at Kaiser and many other places, treatment decisions are based on observed, single measurements, often without rest. As a result, blood pressures are perhaps 5-10 mm Hg higher than they would be if taken using the SPRINT method.
In a review of 73,522 hypertensive patients , the Kaiser investigators found that those treated to a mean systolic BP (SBP) of 122 mm Hg – based on standard office measurement – actually had worse outcomes than did those treated to a mean of 132 mm Hg, with a greater incidence of cardiovascular events, hypotension, electrolyte abnormalities, and other problems.
“The way SPRINT measured BP was systematically different than the BPs we rely on to treat patients in clinical practice. We think that, unless you are going to implement a SPRINT-like protocol, aiming for a slightly higher target of around a mean of 130-132 mm Hg will achieve optimal outcomes. You are likely achieving a SPRINT BP of around 120-125 mm Hg,” said Alan Go, MD, director of the comprehensive clinical research unit at Kaiser Permanente of Northern California, Oakland.
Meanwhile, “if you [treat] to 120 mm Hg, you are probably getting around a SPRINT 114 mm Hg. That runs the risk of hypotension, which we did see. There is also the potential for coronary ischemia because you are no longer providing adequate coronary perfusion,” he said at the American Heart Association scientific sessions.
In their “SPRINT to translation” study, Dr. Go and his team reviewed Kaiser’s electronic medical records to identify patients with baseline BPs of 130-180 mm Hg who met SPRINT criteria and then evaluated how they fared over about 6 years of blood pressure management, with at least one BP taken every 6 months; 7,213 patients were treated to an SBP of 140-149 mm Hg and a mean of 143 mm Hg; 44,847 were treated to an SBP of 126-139 mm Hg and a mean of 132 mm Hg; and 21,462 were treated to 115-125 mm Hg and a mean of 122 mm Hg.
After extensive adjustment for potential confounders, patients treated to 140-149 mm Hg, versus those treated to 126-139 mm Hg, had a 70% increased risk of the composite outcome of acute MI, unstable angina, heart failure, stroke, and cardiovascular death, and a 28% increased risk of all-cause mortality. They also had an increased risk of acute kidney injury, electrolyte abnormalities, and other problems.
More surprisingly, patients treated to 115-125 mm Hg, again versus those treated to 126-139 mm Hg, also had an increased risk of the composite outcome of 9%. They had lower rates of MI and ischemic stroke, but higher rates of heart failure and cardiovascular death. There was also a 17% increased risk of acute kidney injury and a 51% increased risk of hypotension requiring ED or hospital treatment, as well as more electrolyte abnormalities.
The 115-125 mm Hg group also had a 48% increased risk of all-cause mortality. The magnitude of the increase suggests that low blood pressure was a secondary effect of terminal illness in some cases, but Dr. Go didn’t think that was the entire explanation.
The participants had a mean age of 70 years; 63% were women and 75% were white. As in SPRINT, patients with baseline heart failure, stroke, systolic dysfunction, diabetes, end-stage renal disease, and cancer were among those excluded.
There was no external funding for the work, and the investigators didn’t have any disclosures.