Landmark Hypertension Trial Favors More Aggressive Blood Pressure Control

By George Thomas, MD, MPH, FACP

Intensively managing high blood pressure in older adults to achieve systolic levels below commonly recommended hypertension targets significantly reduces cardiovascular disease rates and mortality risk, according to the preliminary results of a landmark federally sponsored study.

Hypertension is highly prevalent in the U.S. adult population and it is an established risk factor for heart disease, stroke, heart failure and kidney disease. Observational studies show a progressive increase in cardiovascular risk associated with blood pressure (BP) levels above 115/75 mm Hg.

While it is well-established that reducing elevated BP lowers cardiovascular risk, the optimal BP goal for patients with a diagnosis of hypertension and who are being treated has been a matter of debate. Should clinicians try to lower BP to “optimal levels,” i.e., less than 120/80 mm Hg? Would such an approach be beneficial or harmful? Would it be costly or burdensome to patients?

Current clinical practice, endorsed by hypertension guidelines, is to try to lower systolic blood pressure (SBP) to less than 140 mm Hg in most patients. The recent report from the Joint National Committee (JNC 8) recommends relaxing BP goals in elderly patients to aim for SBP of less than 150 mm Hg, citing lack of evidence for more aggressive control.

Cleveland Clinic’s Department of Nephrology and Hypertension is involved in the Systolic Blood Pressure Intervention Trial (SPRINT), a multi-center, randomized controlled trial sponsored by the National Institutes of Health (NIH) that aimed to answer the following question: Will more aggressive BP control to SBP < 120 mm Hg (intensive group) reduce the risk of cardiovascular, kidney and cognitive outcomes, compared with the current standard practice of BP control to SBP < 140 mm Hg (standard group)?”

The study enrolled volunteers age 50 and above with established cardiovascular disease or cardiovascular risk factors, with particular emphasis on patients with chronic kidney disease (CKD) with estimated glomerular filtration rate (GFR) of 20-50 ml/min/1.73 m2, and patients aged 75 years and older. Patients with diabetes, stroke or polycystic kidney disease were not included (as other studies aimed to answer the question in these patients).

The study’s primary outcome was the first occurrence of a myocardial infarction, acute coronary syndrome, stroke, heart failure or cardiovascular disease death. Secondary outcomes included all-cause mortality, decline in kidney function, development of end-stage renal disease, dementia, decline in cognitive function or small vessel cerebral ischemic disease.

Between 2010 and 2013, 9,361 participants from 102 study sites were recruited and randomly assigned to the two groups noted above. The average age of study participants was 68 years; about 36 percent were female and 30 percent were black. Twenty-eight percent of the participants were older than 75, and 28 percent had baseline CKD (9.5 percent of participants had an estimated GFR of less than 45 ml/min/1.73 m2). Clinical center investigators had the discretion to select anti-hypertensive medications at initiation or intensification of therapy to achieve and maintain BP targets in participants based on their randomization group. Follow-up was planned through 2016.

The NIH recently announced SPRINT’s initial results. Based on preliminary analysis and recommendations from the study’s Data Safety Monitoring Board, the intervention portion of the study was stopped early, as there was clear superiority in the intensive group with regard to outcomes. The adjudicated results through March 2015 showed a significant 30 percent lower incidence for primary outcome and a 25 percent lower risk of death in participants in the intensive group compared with the standard group.

Other study results are still being analyzed, particularly with regard to outcomes in specific subgroups, such as patients aged 75 and older and patients with CKD. Details regarding adverse events (including kidney problems and falls with injuries) are still to come, although the preliminary results state that benefits of intensive treatment outweigh risks.

Although the intervention portion of the study has been stopped, SPRINT investigators will continue to examine participants to ascertain other outcomes (particularly cognitive outcomes) through mid-2016.

In summary, preliminary results from this landmark trial now provide robust scientific evidence favoring aggressive blood pressure control in patients with established cardiovascular disease or cardiovascular risks (without a history of diabetes or stroke).

These results will obviously influence future hypertension guidelines and clinical practice. Until more information from the study is available, clinicians should work with patients to establish individual BP goals, taking into account patient factors including treatment tolerability, occurrence of side effects, frailty and cost.

As Cleveland Clinic’s principal investigator in the SPRINT trial, I am available at 216.636.5420 to answer study-related questions. You may also contact Jennifer Maraschky (Cleveland Clinic SPRINT research coordinator) at 216.444.7954.

The Department of Nephrology and Hypertension within Cleveland Clinic’s Glickman Urological & Kidney Institute has a rich history of innovation and research in hypertension. The Department’s Center for the Study of Blood Pressure Disorders is certified by the American Society of Hypertension (ASH) as a Comprehensive Hypertension Center. It provides specific expertise in blood pressure management and is staffed by ASH-certified hypertension specialists.