Impact of Cardiovascular Risk on the Relative Benefit and Harm of Intensive Treatment of Hypertension

Background: The lower rate of primary outcome events in the intensive treatment group in SPRINT (Systolic Pressure Intervention Trial) was associated with increased clinically significant serious adverse events (SAEs). In 2017, the American College of Cardiology/American Heart Association issued risk-based blood pressure treatment guidelines. The authors hypothesized that stratification of the SPRINT population by degree of future cardiovascular disease (CVD) risk might identify a group which could benefit the most from intensive treatment. Objectives: This study investigated the effect of baseline 10-year CVD risk on primary outcome events and all-cause SAEs in SPRINT. Methods: Stratifying by quartiles of baseline 10-year CVD risk, Cox proportional hazards models were used to examine the associations of treatment group with the primary outcome events and SAEs. Using multiplicative Poisson regression, a predictive model was developed to determine the benefit-to-harm ratio as a function of CVD risk. Results: Within each quartile, there was a lower rate of primary outcome events in the intensive treatment group, with no differences in all-cause SAEs. From the first to fourth quartiles, the number needed to treat to prevent primary outcomes decreased from 91 to 38. The number needed to harm for all-cause SAEs increased from 62 to 250. The predictive model demonstrated significantly increasing benefit-to-harm ratios (± SE) of 0.50 ± 0.15, 0.78 ± 0.26, 2.13 ± 0.73, and 4.80 ± 1.86, for the first, second, third, and fourth quartile, respectively (p for trend <0.001). All possible pairwise comparisons of between-quartile mean values of benefit-to-harm ratios were significantly different (p < 0.001). Conclusions: In SPRINT, those with lower baseline CVD risk had more harm than benefit from intensive treatment, whereas those with higher risk had more benefit. With the 2017 American College of Cardiology/American Heart Association blood pressure treatment guidelines, this analysis may help providers and patients make decisions regarding the intensity of blood pressure treatment.