A new analysis combining data from the SPRINT and ACCORD-BP trials suggests that intensive blood pressure lowering is associated with improved stroke-free survival in high-risk patients. The study, published in Scientific Reports, examined the impact of targeting a systolic blood pressure (SBP) of less than 120 mmHg compared to a standard target of less than 140 mmHg on the combined outcome of stroke and death.
The researchers pooled participant-level data from the SPRINT (Systolic Blood Pressure Intervention Trial) and ACCORD-BP (Action to Control Cardiovascular Risk in Diabetes-Blood Pressure) trials. SPRINT investigated intensive versus standard BP control in individuals at high cardiovascular risk without diabetes, while ACCORD-BP focused on patients with type 2 diabetes mellitus. The combined dataset included over 14,000 participants.
Stroke-Free Survival Analysis
The primary outcome of the analysis was stroke-free survival (SFS), defined as the time to either stroke or death, whichever occurred first. This composite endpoint is considered clinically relevant as it captures the most severe potential consequences of hypertension.
The results indicated that intensive blood pressure lowering was associated with a statistically significant improvement in SFS compared to standard treatment. The cumulative incidence rates of SFS were estimated using Kaplan-Meier curves, and the difference between the two treatment groups was assessed using the log-rank test. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using a stratified Cox proportional hazards model to account for the clustering of patients from the same trial.
Risk Stratification and Individualized Treatment
The researchers also explored whether the benefits of intensive blood pressure control varied across different risk groups. They assessed heterogeneity of treatment effect (HTE) across tertiles of individual stroke probability based on the revised Framingham Stroke Risk Score (R-FSRS). This score incorporates factors such as age, smoking status, prevalent cardiovascular disease, atrial fibrillation, diabetes mellitus, antihypertensive treatment, and SBP.
The analysis revealed potential differences in treatment effect across the R-FSRS strata, suggesting that individualized risk assessment could help tailor blood pressure targets to maximize benefits and minimize potential harms. The number needed to treat (NNT) to achieve one additional stroke-free survivor was also estimated for each R-FSRS stratum.
Trial Details and Ethical Considerations
The SPRINT trial excluded participants with a history of stroke, while the ACCORD-BP trial had a very low number of participants with prior stroke. Both trials received ethical approval from the institutional review boards of participating study sites and adhered to the International Conference on Harmonization guidelines. Participants provided written informed consent, and the data used in the analysis were anonymized.
The U.S. National Heart, Lung, and Blood Institute (NHLBI) initiated the SPRINT trial, with co-sponsorship from other institutes. The ACCORD trials were also sponsored by the NHLBI. The data have been made publicly available and can be requested at a specified website upon approval.
