Detecting Heterogeneous Treatment Effects to Guide Personalized Blood Pressure Treatment: A Modeling Study of Randomized Clinical Trials.

Basu S, Sussman JB, Hayward RA. Detecting Heterogeneous Treatment Effects to Guide Personalized Blood Pressure Treatment: A Modeling Study of Randomized Clinical Trials. Annals of internal medicine. 2017 Mar 7; 166(5):354-360.

Related HSR&D Project(s)

• CDA 13-021 – Implementation research of benefit-based treatment for cardiovascular disease

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Abstract:

Background: Two recent randomized trials produced discordant results when testing the benefits and harms of treatment to reduce blood pressure (BP) in patients with cardiovascular disease (CVD). Objective: To perform a theoretical modeling study to identify whether large, clinically important differences in benefit and harm among patients (heterogeneous treatment effects [HTEs]) can be hidden in, and explain discordant results between, treat-to-target BP trials. Design: Microsimulation. Data Sources: Results of 2 trials comparing standard (systolic BP target < 140 mm Hg) with intensive (systolic BP target < 120 mm Hg) BP treatment and data from the National Health and Nutrition Examination Survey (2013 to 2014). Target Population: U.S. adults. Time Horizon: 5 years. Perspective: Societal. Intervention: BP treatment. Outcome Measures: CVD events and mortality. Results of Base-Case Analysis: Clinically important HTEs could explain differences in outcomes between 2 trials of intensive BP treatment, particularly diminishing benefit with each additional BP agent (for example, adding a second agent reduces CVD risk [hazard ratio, 0.61], but adding a fourth agent to a third has no benefit) and increasing harm at low diastolic BP. Results of Sensitivity Analysis: Conventional treat-to-target trial designs had poor ( < 5%) statistical power to detect the HTEs, despite large samples (n  > 20 000), and produced biased effect estimates. In contrast, a trial with sequential randomization to more intensive therapy achieved greater than 80% power and unbiased HTE estimates, despite small samples (n  = 3500). Limitations: The HTEs as a function of the number of BP agents only were explored. Simulated aggregate data from the trials were used as model inputs because individual-participant data were not available. Conclusion: Clinically important heterogeneity in intensive BP treatment effects remains undetectable in conventional trial designs but can be detected in sequential randomization trial designs. Primary Funding Source: National Institutes of Health and U.S. Department of Veterans Affairs.