Study Design
This prospective study employed a pre/post design to evaluate
the effectiveness of a pill box clinic over a 4-week period for the
management of uncontrolled hypertension at a rural Veterans
Affairs Medical Center (VAMC). The study complied with the
Declaration of Helsinki and the International Conference on
Harmonization/Good Clinical Practice Guidelines and was
approved by the on-site VAMC Institutional Review Board
(IRB). All study investigators were pharmacists at the VAMC
during the study period.
The primary outcome was reduction of systolic BP (SBP)
by 10 mmHg from pre-intervention to post-intervention.
Secondary outcomes were percentage of patients meeting goal
BP as defined by JNC7 and patient adherence to antihypertensive
medications. Goal BP was defined as < 130/80 mmHg
for patients with a diagnosis of diabetes mellitus (DM) and
< 140/90 mmHg for all other patients. Patient adherence to
antihypertensive medications was assessed at the 2 follow-up
appointments from pill counts conducted by a pharmacist.
Antihypertensive medication adherence was calculated using
the medication possession ratio (MPR), a comparison of the
number of doses the patient missed and the number of prescribed
doses during a defined time.20 MPR is equivalent to the
number of doses taken over a specified time period, divided
by the number of doses prescribed over the same time period.
An MPR of ≥ 80% was considered adherent, as is standard in
clinical practice.21
Based on pharmacokinetics of antihypertensive medications,
lack of need for laboratory evaluation, and a sole purpose
to evaluate change in BP with implementation of pill box use,
we decided that a change in BP could be evaluated within a
matter of weeks rather than months. Therefore, the duration of
this study was approximately 4 weeks