Cardiology · 2015
SPRINT (Systolic Blood Pressure Intervention Trial)
The 140/90 mmHg threshold had governed hypertension management for most of three decades. JNC 7 in 2003 reinforced it as the standard target for most adults, with a lower 130/80 goal for diabetics and patients with chronic kidney disease. Observational data had long suggested that cardiovascular risk continued to rise above 115 mmHg systolic without any clear inflection point, but randomized trials had not confirmed that targeting below 140 added benefit in broad populations. The ACCORD-BP trial, published in 2010, found no advantage of intensive control below 120 mmHg in diabetics, cooling enthusiasm for lower targets.
SPRINT was designed to test the question in a different population: adults aged 50 and older with elevated cardiovascular risk but without diabetes or prior stroke. The National Heart, Lung, and Blood Institute funded the trial across 102 clinical sites in the United States and Puerto Rico. Paul Whelton of Tulane University chaired the steering committee. Among the 9,361 participants randomized, half targeted systolic pressure below 120 mmHg (intensive arm) and half below 140 mmHg (standard arm). The independent data monitoring board halted the trial in September 2015, about one year before the planned completion, because the intensive group had already achieved a 25% reduction in major cardiovascular events and a 27% reduction in all-cause mortality.
The results landed in a field primed for debate. Critics immediately noted that SPRINT used an unattended automated blood pressure measurement protocol, in which patients sat alone in a room for several minutes before readings were taken. Clinic blood pressures measured in the usual attended fashion typically run 5 to 10 mmHg higher, meaning the 120 mmHg intensive target in SPRINT may have corresponded to roughly 130 to 135 mmHg in ordinary practice. That methodological difference blunted the apparent gap between arms and made direct comparisons to other trials difficult.
A second criticism was the exclusion of diabetics and patients with prior stroke, precisely the populations in which aggressive blood pressure lowering had previously been tested and found either neutral (ACCORD-BP) or potentially harmful (the J-curve hypothesis in ONTARGET). SPRINT's population was older, with a mean age of 68, and nearly 30% had chronic kidney disease at baseline. Serious adverse events, including hypotension, syncope, electrolyte abnormalities, and acute kidney injury, were more frequent in the intensive arm.
Despite those caveats, the 2017 ACC/AHA hypertension guidelines incorporated SPRINT as the primary evidence base for a new 130/80 threshold, replacing the old 140/90 standard for most adults. Jackson Wright and other investigators who helped design the intensive protocol defended the unattended measurement approach as more reproducible and less subject to white-coat effect. The guideline change reclassified tens of millions of Americans as hypertensive and generated ongoing controversy about whether widespread treatment at lower thresholds would translate to the same risk-benefit profile seen in the controlled trial.
Key People
- Paul Whelton — Chair of SPRINT steering committee; helped draft 2017 ACC/AHA guidelines
- Jackson Wright — Co-investigator; helped design the intensive-treatment protocol
- Lawrence Fine — NHLBI project officer; oversaw federal funding and trial oversight
- William Cushman — Investigator; led blood pressure measurement standardization efforts
N Engl J Med. 2015;373(22):2103-2116.
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