Beneficial effect of intensive blood pressure control on cardiovascular and all-cause mortality not persist after trial intervention – a secondary analysis of the SPRINT trial

1. Intensive blood pressure control regime was associated with improved cardiovascular and all-cause mortality at a median follow-up point of 3.3 years.

2. After a median of 8.8 years, there was no significant improvement in mortality rates between patients who had undergone intensivist versus consistent blood pressure control.

Level of Evidence Rating: 1 (Excellent)

Study Rundown: Essential hypertension is a common risk factor for cardiovascular disease and associated mortality. Fortunately, it is modifiable, and high-quality studies have shown that pharmacological blood pressure control interventions can effectively reduce cardiovascular and all-cause mortality associated with high blood pressure. Recent trials demonstrated that mortality was lowered with intensive antihypertensive treatment although their follow-up duration was limited. The present study sought to determine whether the mortality benefits of intensive antihypertensive control persist long-term in comparison to standard, consistent blood pressure control strategies.

9361 participants were randomized in total to the intensive or consistent blood pressure control groups with 120 mmHg or 140 mmHg targets, respectively. The total median follow-up time was 8.8 years in both groups. There was a mortality benefit to intensive treatment compared to consistent treatment during the trial phase (less than 3 years follow-up) but not at the trial endpoint. This trend was true for both cardiovascular mortality as well as all-cause mortality. The benefit of intensive blood pressure control from a cardiovascular mortality standpoint extended from 2.3 to 5.6 years of follow-up, after which point it was not significantly better than consistent blood pressure control.

The present study concluded that intensive blood pressure control to a target systolic blood pressure of 120 mmHg is beneficial in lowering mortality risk in the short term compared to consistent blood pressure control at a higher target (140 mmHg), but that this effect is not persistent beyond approximately 5 years. A major strength of this study is the large sample size and long-term follow-up period. However, this work has limited external validity as the trial population was highly selected to exclude many common comorbidities.

Click here to read this study in JAMA Cardiology

Click to read an accompanying editorial in JAMA Cardiology

Relevant reading: A randomized trial of intensive versus standard blood pressure control

In-Depth [randomized controlled trial]: A multi-center randomized controlled trial was performed. Eligible participants were aged 50 or greater and had an index blood pressure measurement of between 130-180 mmHg. High-risk features included cardiovascular disease, chronic kidney disease, or a Framingham risk score greater than 14% if above age 75. Patients with a history of dementia, diabetes, stroke, polycystic kidney disease or proteinuria were excluded, as were residents of nursing homes. Patients were randomized in a 1:1 ratio to undergo antihypertensive treatment targeting a systolic blood pressure of either 120 mmHg (intensive group) or 140 mmHg (consistent group) over a 5-year period. Standardized equipment and procedures were used to measure blood pressure across study sites.

A total of 818 (intensive group) and 826 (consistent group) deaths occurred amongst trial participants during the study period due to any cause. The hazard ratio for all-cause mortality in the intensive versus consistent groups was 0.83 (95% confidence interval 0.68-1.01) during the first three years of the trial and 1.08 (95% confidence interval 0.94-1.23) thereafter. At the trial endpoint, the total number of deaths from cardiovascular causes was 248 in the intensive group and 273 in the consistent group. The hazard ratio for cardiovascular mortality was 0.66 (0.49-0.89) during the trial phase and 1.02 (0.84-1.24) at the trial endpoint.

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