Implications of SPRINT: How Should Clinicians Respond?
SPRINT trial results have been dramatic, but are the lower blood pressure targets appropriate for every patient?
Reverberations from SPRINT (Systolic Blood Pressure Intervention Trial) continue to be felt, with many physicians potentially unsure about how to apply the results in clinical practice.
The clinical trial included 9361 participants with a systolic blood pressure (SBP) of 130 mm Hg or higher and an increased cardiovascular risk, but without diabetes, randomly assigned to a SBP target of <120 mm Hg (intensive treatment) or a target of <140 mm Hg (standard treatment).1
Findings published in the November 2015 issue of New England Journal of Medicine indicated that patients in the intensive treatment group had a 25% risk reduction in the primary composite end point of major cardiovascular events (eg, myocardial infarction, non–myocardial infarction acute coronary syndrome, stroke, acute decompensated heart failure, and cardiovascular disease death) and a 27% risk reduction in mortality compared with those who received standard treatment.1
These dramatic results seemingly confounded the already contentious conclusions reached by the Eighth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 8), whose 2014 Evidence-Based Guidelines for the Management of High Blood Pressure in Adults set the systolic threshold for treatment of patients older than 60 years of age at ≥150 mmHg and at ≥140 mmHg for younger patients.2
In a February 2016 editorial published in Journal of the American College of Cardiology, Dr Alan Gradman of Temple University School of Medicine in Philadelphia, cautioned that the inclusion of disparate subgroups of high-risk patients in SPRINT made it difficult to generalize about which patients stand to benefit from intensive BP treatment. He wrote, “A patient may belong to a subgroup (eg, patients with coronary artery disease) that made a very small statistical contribution to the overall results. It is possible that a study conducted exclusively in that subgroup would yield very different results.”3
Cardiology Advisor invited Dr Gradman and 2 members of the SPRINT research group, Dr Margaret Conroy of the University of Pittsburgh School of Medicine in Pittsburgh and Dr Julia Lewis of Vanderbilt University School of Medicine in Nashville, to weigh in on the clinical implications of the SPRINT trial via email. Interviews have been edited for clarity.
Cardiology Advisor: SPRINT authors concluded that “SPRINT now provides evidence of benefits for an even lower SBP target than that currently recommended in most patients with hypertension." Should the findings in SPRINT be extrapolated to the majority of patients with hypertension?
Dr Conroy: I do not think that SPRINT findings can be applied to all patients with hypertension, and I am not sure that was the authors' meaning in the conclusion. Even if we just applied them to the higher risk patients (similar to those in SPRINT), this would still mean in change in care for a very large number of high-risk patients with hypertension.
Dr Lewis: SPRINT results only apply to the kinds of patients studied in SPRINT. It is important to note that an almost identical study done in patients with diabetes and no significant kidney disease [Note: see the ACCORD trial4] was unable to demonstrate benefit of the low BP goal and did show significant adverse events associated with it. So it does not apply to all patients. Patients studied in the SPRINT study however had a tremendous benefit. These were non-diabetic patients with hypertension and cardiovascular risk factors and/or chronic kidney disease.
Dr Gradman: The authors say “most patients” and they are probably right. However, as we have seen in ACCORD and SPRINT, 2 studies using the same BP targets may yield different results. In ACCORD, the higher target led to better results—the opposite of SPRINT.4 The difference is the patient population; ACCORD included all diabetics and SPRINT included none. The goal is to determine which categories of patients should be treated to the lower target.
Cardiology Advisor: Is it likely that clinical guidelines will be changed in light of SPRINT findings? Should they be?
Dr Conroy: I think it is likely that BP guidelines will be changed and agree that they should be. The 2014 Guidelines from the JNC 8 were met with quite a bit of controversy, including a dissenting opinion from some of those who served on that guideline committee.
Dr Lewis: Clinical guidelines should and will be changed. SPRINT demonstrated highly statistically significant and clinically significant benefits in reducing deaths and cardiovascular events.
Dr Gradman: It is likely that guidelines will be changed to include the SPRINT results. They should be: the pendulum swung too far toward less aggressive targets after ACCORD (which was done by the same research group at the National Heart, Lung, and Blood Institute). However, as my editorial points out, it is not appropriate to include every patient that was included in SPRINT in any new recommendations for lower targets.