SPRINT: Patients at most risk derive greatest benefit from intensive BP lowering
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Patients with the highest baseline risk factors derived the most benefit from an intensive BP-lowering regimen compared with standard care, according to a secondary analysis of the SPRINT trial.
“In this predictive modeling analysis of SPRINT, higher baseline predicted CVD risk was associated with greater clinical benefit (ie, greater absolute CVD risk reduction) with intensive vs. standard systolic BP treatment,” Adam P. Bress, PharmD, MS, associate professor of population health sciences with tenure in the division of health system innovation at the University of Utah, and colleagues wrote. “The implication of these results is that SPRINT-eligible patients at higher risk for CVD should be prioritized for intensive systolic BP treatment. Predicted CVD benefit and increased treatment-related adverse risk with intensive treatment are highly correlated. Most participants with high predicted benefit also had greater predicted absolute risk increases for treatment-related adverse events.”
As Healio previously reported, in the main results of SPRINT, a systolic BP target of less than 120 mm Hg was associated with lower rates of death and CV events compared with a target of less than 140 mm Hg.
For this secondary analysis of SPRINT published in the Journal of the American Heart Association, researchers evaluated 8,828 participants (mean age, 68 years; 35% women) to determine the magnitude of benefit and risk for adverse events from intensive vs. standard systolic BP treatment. There were two benefit-related outcomes: a CVD composite of MI or other ACS, stroke, HF or CVD death; and all-cause mortality. Treatment-related adverse events included hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls and acute kidney injury.
Intensive vs. standard treatment
Researchers reported that models predicting each outcome performed well according to C statistics and the Greenwood-Nam-D’Agostino (GND) test for the CVD composite outcome (C statistic = 0.71; P for GND = .48), all-cause mortality (C statistic = 0.75; P for GND = .18) and treatment-related adverse events (C statistic = 0.69; P for GND = .68).
According to the analysis, baseline risk factors most strongly associated with higher risk for the CVD composite outcome were older age, history of CVD and impaired kidney function.
The predicted magnitude of benefit at 3.26 years of intensive compared with standard systolic BP treatment in terms of absolute risk reduction grew as baseline risk increased for both the CVD composite outcome (C-for-benefit = 0.549; 95% CI, 0.496-0.602) and all-cause mortality (C-for-benefit = 0.549; 95% CI, 0.48-0.618). However, for treatment-related adverse events, the association was attenuated at the highest levels of baseline risk (C-for-benefit = 0.571; 95% CI, 0.511-0.631).
According to the study, the overall predicted magnitude of benefit of intensive systolic BP treatment compared with standard treatment was associated with the predicted increased risk for treatment-related adverse events, with Spearman correlation coefficients of 0.72 for treatment-related adverse events vs. the CVD composite outcome and 0.76 for treatment-related adverse events vs. all-cause mortality.
Moreover, 95% of participants who fell into the highest range of predicted benefit for the CVD composite outcome also had high or moderately increased risk for treatment-related adverse events.
Researchers also noted that only 1.8% of participants were classified as high benefit with low risk for treatment-related adverse events and 1.5% were classified as low benefit with high risk for treatment-related adverse events.
The ‘treatment-risk paradox’
“Clinicians are subject to many biases that lead to the ‘treatment-risk paradox’ — the scenario where patients at high risk for adverse events receive less-intensive treatment than patients at lower risk. Some of the clinicians’ concerns are rational,” Joseph A. Diamond, MD, associate professor of cardiology at the Donald and Barbara Zucker School of Medicine at the Hofstra/Northwell School of Medicine, and colleagues wrote in a related editorial. “Given the conflicting blood pressure guidelines that have been issued over the past several years, the results of the current study, in conjunction with other secondary analyses of SPRINT, offer an evidence-based rationale that nudge physicians to overcome the treatment-risk paradox in blood pressure management.”
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