Assessing medication adherence simultaneously by electronic monitoring and pill count in patients with mild-to-moderate hypertension.
BACKGROUND
Poor adherence to antihypertensive medication is one of the major problems in the treatment of hypertension. Electronic monitoring is currently considered to be the gold standard for assessing adherence, but it may trigger patients to open the pill bottle without taking medication or to take out more than prescribed. In adjunct to electronic monitoring, pill count could be a valuable tool for exploring adherence patterns, and their effects on blood pressure reduction.


METHODS
Among a total of 228 patients with mild-to-moderate hypertension, adherence to treatment was measured by means of both the Medication Event Monitoring System (MEMS) and pill count. Patients were followed-up for seven visits over a period of 1 year. At each visit to the physician's office, patient's adherence was assessed by both methods.


RESULTS
Adherence is defined as the percentage of days with correct dosing; median adherence according to MEMS was lower than median adherence according to pill count (91.6 vs. 96.1; P < 0.001). Both methods agreed in defining patients as adherent in 107 (47%) and nonadherent in 33 (14%) patients. Thirty-one (14%) patients were adherent only by MEMS and 59 (25%) patients only by pill count. At the end of the study, patients in the four categories reached comparable blood pressure values and reductions.


CONCLUSIONS
Pill count could be a useful adjunct to electronic monitoring in assessing adherence patterns. Although deviant intake behavior occurred frequently, the effect on achieved blood pressure and blood pressure reduction was not remarkable.
van Onzenoort
Hein A W
HA
Department of Clinical Pharmacy, University Medical Center St Radboud, Nijmegen, The Netherlands.
Verberk
Willem J
WJ
Kessels
Alfons G H
AG
Kroon
Abraham A
AA
Neef
Cees
C
van der Kuy
Paul-Hugo M
PH
de Leeuw
Peter W
PW
D000368:Aged; D017311:Amlodipine / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D001795:Blood Pressure Determination; D004311:Double-Blind Method; D004349:Drug Packaging / Q000706:statistics & numerical data; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D017706:Lisinopril / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011446:Prospective Studies; D013607:Tablets; D016903:Drug Monitoring
D000959:Antihypertensive Agents; D013607:Tablets; D006852:Hydrochlorothiazide; D017311:Amlodipine; D017706:Lisinopril