Effect of blood pressure control on sudden death risk score in the SPRINT trial

Background: Recent data suggest that population screening for risk of sudden cardiac death (SCD) may be feasible with risk scores that can be implemented in the electronic health record. But, there are no established therapeutic strategies to target lowering risk for SCD in the general population. Our aim was to evaluate the effect of the Systolic Blood Pressure Intervention Trial (SPRINT) intensive blood pressure intervention on SCD risk and cardiovascular (CV) outcomes. Methods: We conducted a prospective cohort study within the SPRINT trial including all participants who had information required to calculate a SCD score. We classified SPRINT participants at baseline by randomized arm into high, intermediate and low SCD risk and followed them for a period of 12 months. We determined changes in SCD risk by comparing the baseline SCD risk score with the 12-month recalculated SCD risk score and determined the incidence of the primary SPRINT outcome and all-cause mortality. We used both linear regression and Cox proportional models to evaluate outcomes adjusted for CV risk, prevalent CV diseases, and randomization site. Results: We included 8052 SPRINT participants who met our inclusion criteria. The median baseline SCD score was 2.7% SCD per 10 years; 95% CI 1.6 to 4.7 for both randomized arms. At 12-month follow-up, the median SCD score for the intensive group was 5.5 (2.0–20) while the standard group was 6.8 (2.4–26) p<0.01. Over a follow-up period of 3.8 years, in the intensive arm, the HR for those who had a reduction in SCD risk score was 0.80; 95% CI 0.62–0.98 for the primary event while the HR for the standard arm was 1.01; 95% CI 0.81–1.26. The changes in SCD risk were mediated by decreases in blood pressure and an increase in diabetes incidence as well as age. Conclusions: SCD risk changed in SPRINT because of intensive blood pressure control and those who changed their score had fewer cardiovascular events. Future studies should target comprehensive interventions targeting all modifiable risk factors.