Systolic Blood Pressure Intervention Trial

The Systolic Blood Pressure Intervention Trial (SPRINT) is a multi-center clinical trial that was performed from 2010 to 2015, and published in November 2015.^[1]

The objective of the trial was to identify whether, in patients with a systolic blood pressure of 130 mm Hg or higher and an increased cardiovascular risk, but without diabetes, treating to a systolic blood pressure target of less than 120 mm Hg is superior to a target of 140 mm Hg.^[1] The primary outcome being measured was myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes.^[1] The study implies that patients receiving "standard" therapy were controlled similarly to all adults being treated for hypertension and that patients receiving "intensive" therapy had a lower mean SBP compared to all adults being treated for hypertension, but neither conclusion is true when compared to the US National Health and Nutrition Examination Survey.^[2]

During the study, 9361 patients were randomly assigned to either a 140 mm Hg target (standard treatment) or a 120 mm Hg target (intensive treatment).^[1] After being followed up for a median of 3.26 years, the study showed a significantly lower rate of the primary outcome in the intensive treatment group (1.65% per year) compared to the standard treatment group (2.19% per year).^[1] The risk of experiencing a primary outcome (myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes) was 25% lower than in the standard treatment group, and the risk of death from any cause was 27% lower.^[1] The number needed to treat with intensive therapy instead of standard therapy to prevent one death was 90.^[1] The results were so much more superior for the intensive treatment group that the trial was stopped early.^[1]

Although the trial showed that intensive treatment was associated with lower rates of cardiovascular events and death, intensive treatment was also associated with 4% higher rates of serious adverse effects from anti-hypertensive medications, including syncope, electrolyte abnormalities, acute kidney injury or acute renal failure.^[1] However, this association was not statistically significant, with a P-value of 0.25,^[1] and therefore may have occurred by chance. The intensive treatment group were not found to be at a greater risk of injurious falls or bradycardia, and orthostatic hypotension was less common in the intensive treatment group.^[1] The SPRINT study was criticised about the population studied in terms of age, racial and cardiovascular danger^[3]

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