Electronic monitoring of adherence, treatment of hypertension, and blood pressure control.

BACKGROUND Although it is generally acknowledged that electronic monitoring of adherence to treatment improves blood pressure (BP) control by increasing patients' awareness to their treatment, little information is available on the long-term effect of this intervention. METHODS In this observational study among a total of 470 patients with mild-to-moderate hypertension, adherence was measured in 228 patients by means of both the Medication Event Monitoring System (MEMS) and pill count (intervention group), and in 242 patients by means of pill count alone (control group). During a follow-up period of 1 year consisting of seven visits to the physician's office, BP measurements were performed and medication adjusted based on the achieved BP. In addition, at each visit adherence to treatment was assessed. RESULTS On the basis of pill counts, median adherence to treatment did not differ between the intervention group and the control group (96.1% vs. 94.2%; P = 0.97). In both groups, systolic and diastolic BP decreased similarly: 23/13 vs. 22/12 mm Hg in the intervention and control group respectively. Drug changes and the number of drugs used were associated with BP at the start of study, but not with electronic monitoring. CONCLUSIONS In this study, electronic monitoring of adherence to treatment by means of MEMS did not lead to better long-term BP control nor did it result in less drug changes and drug use.