Self-Monitoring of Blood Pressure for Improving Adherence to Antihypertensive Medicines and Blood Pressure Control: A Randomized Controlled Trial

Self-monitoring is reported to have limited efficacy for hypertension management in high-income countries. In this study, we aimed to evaluate the effect of self-monitoring on blood pressure (BP) control in an Iranian population. A randomized controlled trial was conducted on 196 mild to moderate hypertensive patients in an outpatient cardiovascular clinic. Patients in the intervention group received a wrist self-monitoring device and were educated to measure and document their BP daily during the study period (24 weeks). Patients in the control group received usual care. Three follow-up visits with the physician were scheduled for all patients (weeks 4, 12, and 24), and the investigator assessed adherence to medications after each visit (pill counting). The primary outcome (BP) was compared between groups using repeated-measure analysis of variance. One hundred ninety patients completed the study. Systolic BP (144.4 +/- 7.4 vs 145.9 +/- 6.4mm Hg) and diastolic BP (85.5 +/- 6.9 vs. 85.1 +/- 7.7mm Hg) were similar between groups at baseline. The trend of BP was not significantly different between groups during the study period. Systolic and diastolic BP decreased significantly in both groups at the first follow-up visit (systolic BP: 132.6 vs. 133.4mm Hg; diastolic BP: 77.4 vs. 77.2mm Hg). In the intervention group, we observed a small continued decrease in diastolic BP up to week 24 BP (P = 0.01). Both groups showed adherence rates > 95% during the study period. Our study could not confirm that self-monitoring can improve BP control in patients with frequent medical visits.