Effect of self-measurement of blood pressure on adherence to treatment in patients with mild-to-moderate hypertension

Background: Poor adherence to treatment is one of the major problems in the treatment of hypertension. Self blood pressure measurement may help patients to improve their adherence to treatment. Method: In this prospective, randomized, controlled study coordinated by a university hospital, a total of 228 mild-to-moderate hypertensive patients were randomized to either a group that performed self-measurements at home in addition to office blood pressure measurements [the self-pressure group (n = 114)] or a group that only underwent office blood pressure measurement [the office pressure group (n = 114)]. Patients were followed for 1 year in which treatment was adjusted, if necessary, at each visit to the physician's office according to the achieved blood pressure. Adherence to treatment was assessed by means of medication event monitoring system TrackCaps. Results: Median adherence was slightly greater in patients from the self-pressure group than in those from the office pressure group (92.3 vs. 90.9%; P = 0.043). Although identical among both groups, in the week directly after each visit to the physician's office, adherence [71.4% (interquartile range 71-79%)] was significantly lower (P < 0.001) than that at the last 7 days prior to each visit [100% (interquartile range 90-100%)]. On the remaining days between the visits, patients from the self-pressure group displayed a modestly better adherence than patients from the office pressure group (97.6 vs. 97.0%; P = 0.024). Conclusion: Although self-blood pressure measurement as an adjunct to office blood pressure measurement led to somewhat better adherence to treatment in this study, the difference was only small and not clinically significant. The time relative to a visit to the doctor seems to be a more important predictor of adherence.