SPRINT: An Enthusiastic Evaluation
The results of the SPRINT study were revealed at the AHA Scientific Sessions on November 9th. A few months’ earlier, the study was stopped prematurely, with a press release indicating a highly significant positive outcome. As a result, the presentation during AHA 2015 held few surprises.
SPRINT is almost the mirror image of a previous trial, ACCORD. ACCORD was conducted with diabetics, SPRINT in non-diabetics, both with randomization of subjects to a standard arm, with a systolic BP goal of <140 mm Hg, and to an intensive arm with a goal of <120 mm Hg. ACCORD was negative, and SPRINT spectacularly positive. The reasons for this anomaly are complex, but basically ACCORD was underpowered to produce a significant result, with half of the number of subjects than in SPRINT. A big plus in SPRINT was, by design, a significant representation of women, African-Americans, the elderly, and those with CKD and cardiovascular disease or at high risk for cardiovascular disease.
In SPRINT, the composite cardiovascular end-point and also all-cause mortality both showed a lower hazard ratio (25% and 27% respectively) for the intensive group. The benefit of intensive BP lowering was seen in all sub-groups:
- the elderly;
- both genders;
- whether or not there was prior CKD;
- African-Americans and non-African Americans, and
- those with CVD and those without.
I thought that at least two of the findings were quite remarkable. One was that intensive BP lowering had a greater positive impact on older individuals (≥ 75 years) than those who were younger than 75. This should give pause to all of those guideline writing groups who nearly universally recommend higher BP targets for the elderly.
Another surprising finding was that even those with systolic BPs (≤ 132 mm Hg) well within the normotensive range benefit from intensive SBP lowering to < 120 mm Hg. This should be a prompt to radically re-think our definition of hypertension, to emphasize CV risk as a criterion for initiating therapy, rather then the BP value alone.
Will I be planning to change my current blood pressure recommendations based on the results of the study ? Certainly, in those patients who can tolerate a lower BP without any side-effects, either from the lower BP or the drugs required to produce it. Also, I would have no hesitation in suggesting the lower target in a healthy and vigorous > 75-year-old population in a very heterogeneous group. However, I would not recommend a change for the frail or unsteady elderly.
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