The association of intensive blood pressure treatment and non-fatal cardiovascular or serious adverse events in older adults with mortality: Mediation analysis in SPRINT

Abstract

Aims: Randomized clinical trials of hypertension treatment intensity evaluate the effects on incident major adverse cardiovascular events (MACEs) and serious adverse events (SAEs). Occurrences after a non-fatal index event have not been rigorously evaluated. The aim of this study was to evaluate the association of intensive (<120 mmHg) to standard (<140 mmHg) blood pressure (BP) treatment with mortality mediated through a non-fatal MACE or non-fatal SAE in 9361 participants in the Systolic Blood Pressure Intervention Trial. Methods and results: Logistic regression and causal mediation modelling to obtain direct and mediated effects of intensive BP treatment. Primary outcome was all-cause mortality (ACM). Secondary outcomes were cardiovascular (CVM) and non-CV mortality (non-CVM). The direct effect of intensive treatment was a lowering of ACM [odds ratio (OR) 0.75, 95% confidence interval (CI): 0.60-0.94]. The MACE-mediated effect substantially attenuated (OR 0.96, 95% CI: 0.92-0.99) ACM, while the SAE-mediated effect was associated with increased (OR 1.03, 95% CI: 1.01-1.05) ACM. Similar patterns were noted for intensive BP treatment on CVM and non-CVM. We also noted that SAE incidence was 3.9-fold higher than MACE incidence (13.7 vs. 3.5%), and there were a total of 365 (3.9%) ACM cases, with non-CVM being 2.6-fold higher than CVM [2.81% (263/9361) vs. 1.09% (102/9361)]. The SAE to MACE and non-CVM to CVM preponderance was found across all age groups, with the ≥80-year age group having the highest differences. Conclusion: The current analytic techniques demonstrated that intensive BP treatment was associated with an attenuated mortality benefit when it was MACE-mediated and possibly harmful when it was SAE-mediated. Current cardiovascular trial reporting of treatment effects does not allow expansion of the lens to focus on important occurrences after the index event.