Impact of a pill box clinic to improve systolic blood pressure in veterans with uncontrolled hypertension taking 3 or more antihypertensive medications.

BACKGROUND

Two-thirds of Americans who are prescribed antihypertensive medications are not at a blood pressure (BP) goal of <140/90 mmHg, and low adherence is identified as a primary cause of inadequate control. Improved adherence to antihypertensive medications has been shown to enhance BP control and reduce the risk of cardiovascular complications. This study investigated the effectiveness of a pill box clinic to improve BP in veterans with uncontrolled hypertension taking 3 or more antihypertensive medications.

OBJECTIVES

To (a) investigate the reduction of systolic BP by 10 mmHg from pre-intervention to post-intervention (primary outcome) and (b) investigate the percentage of patients meeting goal blood pressure--as defined by The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7)--and percentage of patient adherence to antihypertensive medications (secondary outcomes).

METHODS

Patients with uncontrolled hypertension currently taking at least 3 antihypertensive medications were enrolled in this prospective pre/post study. Under the supervision of a pharmacist, each patient was provided two 7-day pill boxes to organize all antihypertensive medications. In addition, baseline BP and previous history of nonadherence were documented. Following the initial encounter, patients attended 2 follow-up appointments, at 2 and 4 weeks, for refill of pill boxes, BP measurement, and adherence assessment. A chi-square test was used for categorical outcomes and logistic regression for nominal outcomes as well as descriptive statistics, as appropriate.

RESULTS

Sixty patients were enrolled, with 50 completing appointments 1 and 2, and 45 completing all 3 appointments. Of those, 24% and 31% achieved at least a 10 mmHg reduction in systolic BP from baseline to appointments 2 and 3, respectively (P = 0.438). Systolic BP readings for appointments 1, 2, and 3 were not statistically significant (mean [SD]: 134.1 [11.8], 131.9 [9.4], and 130.6 [11.4], respectively). Goal BP per JNC7 was achieved by 44% and 51% of patients at appointments 2 and 3, respectively, compared with baseline (P = 0.201). All patients had ≥ 80% adherence to antihypertensive medications, assessed via pill counts at the second and third appointments.

CONCLUSION

Although results were not statistically significant, the pill box clinic resulted in clinically significant reductions in systolic BP by 10 mmHg, as well as an increased number of patients meeting prescribed BP goals.