SPRINT Research Group Summary
Intensive versus Standard Blood-Pressure Control
SPRINT is a research study funded by the National Institutes of Health to answer the following question:
"Will lower blood pressure reduce the risk of heart and kidney diseases, stroke, or age-related declines in memory and thinking?"
Partial results of the SPRINT trial were recently published in the New England Journal of Medicine . Lowering systolic blood pressure (SBP) to < 120 mm Hg in patients at high risk for cardiovascular (CV) events but without diabetes significantly decreased the rates of fatal and nonfatal CV events and death from any cause.
Rates of serious adverse events of hypotension, syncope, electrolyte abnormalities and acute kidney injury or failure, but not of injurious falls, were higher in the intensive-treatment group than in the standard-treatment group.
SPRINT was halted after 3.26 years rather than the planned average of 5 years due to the positive primary outcome. Data is still being collected evaluating cognitive outcomes in the two treatment groups, with results expected in late 2016.
SPRINT is an open-label trial that enrolled 9,361 patients aged 50 years or greater with SBP between 130 and 180 mm Hg, at increased risk of CV events and without diabetes. Patients were randomized to intensive-treatment (SBP < 120 mm Hg) or standard-treatment (SBP < 140 mm Hg). All major antihypertensive medications were permitted to be used in the study.
- The primary composite outcome was myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from CV causes.
- There was a significantly lower rate of the primary composite outcome in the intensive-treatment group than in the standard-treatment group (1.65% per year vs. 2.19% per year; hazard ratio [HR] with intensive treatment, 0.75; 95% confidence interval [CI], 0.64 to 0.89; p < 0.001).
- Numbers needed to treat to prevent a primary outcome event, death from any cause, and death from CV causes during the median 3.26 years of the trial were 61, 90, and 172, respectively.
- Patients in the intensive-treatment group also experienced significantly less secondary outcome events: heart failure (HR, 0.62; p = 0.002), death from CV causes (HR, 0.57; p = 0.005), all-cause mortality (HR, 0.73; p = 0.003) and primary outcome or death (HR, 0.78; p < 0.001).
- Patients in the intensive-treatment group experienced significantly higher rates of hypotension (p = 0.001), syncope (p = 0.05), electrolyte abnormalities (p = 0.02), and acute kidney injury or acute renal failure (p < 0.001).
- In addition, in patients without chronic kidney disease at baseline, there was a decline of at least 30% in estimated glomerular filtration rate in 1.21% of the intensive-therapy group per year vs. 0.35% of the standard-therapy group (p < 0.0001).
Some Key Points from SPRINT:
- There is a need for re-education on proper blood pressure technique. SPRINT followed American Heart Association guidelines using a mean of 3 blood pressures taken while patient was seated, not dangling, after 5 minutes of quiet rest.
- Need to further optimize to full medication doses.
- Potential for intensive therapy with multiple blood pressure medications possibly impacting cost, medication adherence and potential interactions, especially in patients with renal dysfunction
- Patients should continue to home monitor blood pressure.