Comparative Effectiveness of Antihypertensive Therapeutic Classes and Treatment Strategies in the Initiation of Therapy in Primary Care Patients: A Distributed Ambulatory Research in Therapeutics Network (DARTNet) Study

Background: Few comparative effectiveness studies of treatment strategies using antihypertensive therapeutic classes in hypertension control have been assessed in a primary care environment. The objectives are to compare the effectiveness of common antihypertensive therapeutic classes initiated as monotherapy and of fixed-dose combinations (FDCs), free-equivalent combinations (FECs), and monotherapy on hypertension control. Methods: This article reports observational comparative effectiveness analyses of data electronically extracted from electronic health records. The study population consisted of 8,676 patients with an incident prescription for an antihypertensive agent of a total of 79,176 patients receiving antihypertensive therapy in 33 geographically diverse primary care clinics. The main measures were reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) and rates of attaining goals per the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7). Results: There were small, clinically insignificant differences in blood pressure reductions between the monotherapy classes. Higher rates of blood pressure control were obtained when patients were initiated on an angiotensin-converting enzyme inhibitor than a thiazide or thiazide-like diuretic (47.8% vs 39.9%) or a beta-blocker versus a thiazide (45.9% vs 39.9%). Patients initiated on FDCs had significantly larger reductions in blood pressure than patients initiated on FECs (-17.3 vs -12.0 mm Hg SBP; -10.1 vs -6.0 mm Hg DBP) or monotherapy (-17.3 vs -13.6 mm Hg SBP; -10.1 vs -7.9 mm Hg DBP). Rates of attaining JNC7 goals also were better for FDCs than FECs (57.2% vs 42.5%) and for FDCs versus monotherapy (57.2% vs 44.9%). Conclusions: Patients initiated on angiotensin-converting enzyme inhibitors and beta-blockers had slightly higher rates of blood pressure control. The use of FDCs as initial therapy is more effective in the control of hypertension than monotherapy or FECs.