Incremental effectiveness of amlodipine besylate in the treatment of hypertension with single and multiple medication regimens.

BACKGROUND The objective of this retrospective observational analysis is to examine the clinical effectiveness of amlodipine besylate as monotherapy or in combination with other antihypertensive drugs (AHDs) in systolic blood pressure (BP) control and BP goal attainment, according to the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) 6, JNC 7, and American Diabetes Association (ADA)recommendations, within a multicenter ambulatory care setting. METHODS Hypertensive adults (n = 1175) were identified during a 4-year period (1998 to 2001) from a large commercially available electronic medical record (EMR) database. Patients were required to have initiated therapy with amlodipine and have at least one BP measurement within 6 months before, and 12 months after, the medication start date. Patients were divided into cohorts based on the number of AHDs used before, and continued through, the initiation of amlodipine. Mean change in systolic BP was compared from pre- to post-amlodipine, and adjusted change in systolic BP was calculated using multivariate regression. The percentage of patients attaining BP goal was also calculated. RESULTS In the order of increasing number of AHDs before initiation of amlodipine (0, 1, 2, > or = 3 previous AHDs): adjusted systolic BP change in mm Hg was -16.1 (95% confidence interval [CI]: -17.9, -14.3), -17.6 (95% CI: -19.6, -15.5), -16.7 (95% CI: -19.0, -14.5), and -15.7 (95% CI: -18.7, -12.8), respectively; BP goal attainment was 39%, 45%, 41%, and 45%, respectively. Amlodipine initiation in all regimens showed statistically significant incremental systolic BP reduction and BP goal attainment from baseline (P < .001). CONCLUSIONS This study suggests that amlodipine besylate is effective alone or as an add-on therapy to diverse classes of agents.