Measurement of drug compliance by continuous electronic monitoring: a pilot study in elderly patients discharged from hospital.

OBJECTIVE

A pilot study to assess patient compliance with medication by using a new measurement technique, continuous electronic monitoring.

DESIGN

Survey. Compliance monitors were provided to eligible patients at discharge from the hospital to measure drug intake behavior prospectively for a period of 3 weeks.

SETTING

Ambulant patient care after discharge from a geriatric hospital, Krankenhaus Bethanien, which is affiliated with the University Clinic, Heidelberg.

PATIENTS: A consecutive convenience sample of 18 independently living elderly patients (median age 76 years) completed the study. The patients were on maintenance therapy with cardiac glycosides and/or potassium-sparing diuretics prescribed to be taken once daily.

INTERVENTION: The monitoring method provides information about patients' real timing of drug use by continuously recording date and time of openings and closings of the medication containers (monitors). In addition to a standard measure, the percentage of prescribed doses taken, information about regularity of drug use is obtained.

RESULTS

Compliance, percentage of prescribed doses taken, was remarkably variable; it ranged from 24% to 100%, 95% CI: 62%-84%. Mean compliance declined from the first to the third week after discharge, 85% vs 69%, 95% CI: 74%-95% and 56%-81%, respectively (P < 0.05). Omissions of doses, the predominant pattern of non-compliance, were observed in 17 of 18 patients. Regularity of dose timing, as defined by the number of interdose intervals within 24 h +/- 15%, varied from 10% to 100%, 95% CI: 46%-76%.

CONCLUSIONS

Continuous electronic monitoring revealed highly variable compliance in patients prescribed maintenance therapy. Even with a once-daily regimen, persistent and high compliance cannot be assumed. The monitoring technique may be of great value to research and, possibly, to practical therapeutic management.