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.