Total antihypertensive therapeutic intensity score and its relationship to blood pressure reduction

Abstract

Predicting blood pressure (BP) response to antihypertensive therapy is challenging. The therapeutic intensity score (TIS) is a summary measure that accounts for the number of medications and the relative doses a patient received, but its relationship to BP change and its utility as a method to project dosing equivalence has not been reported. We conducted a prospective, single center, randomized controlled trial to compare the effects of Joint National Committee (JNC) 7 compliant treatment with more intensive (<120/80 mm Hg) BP goals on left ventricular structure and function in hypertensive patients with echocardiographically determined subclinical heart disease who were treated over a 12-month period. For this preplanned subanalysis, we sought to compare changes in BP over time with changes in TIS. Antihypertensive therapy was open label. TIS and BP were determined at 3-month intervals with titration of medication doses as needed to achieve targeted BP. Mixed linear models defined antihypertensive medication TIS as an independent variable and change in systolic BP as an outcome measure, while controlling for gender, age, baseline BP, and treatment group. A total of 123 patients (mean age 49.4 ± 8.2 years; 66% female; 95.1% African-American) were enrolled and 88 completed the protocol. For each single point increase in total antihypertensive TIS, a 14.5 (95% confidence interval: 11.5, 17.4) mm Hg decrease in systolic BP was noted (15.5 [95% confidence interval: 13.0, 18.0] mm Hg for those who completed the trial). Total TIS is a viable indicator of the anticipated BP-lowering effect associated with antihypertensive therapy.