Medication adherence is defined as the extent to which patients follow their treatment as prescribed by their healthcare providers. Adherence to treatment is essential for the success of any treatment and poor adherence is associated with a number of adverse effects including disease complications, increased hospitalization, greater healthcare costs and important loss of productivity for patients in the workforce. Nevertheless, poor adherence to treatment remains a frequent issue in patients with chronic diseases, thus requiring the need to develop accurate and innovative methods to correctly identify patients facing difficulties in adhering to their treatment regimens.
Traditional adherence measurement methods include pill counts during a patient’s visit to the hospital or at a patient’s home, self-reports by the patient and adherence computed from the patient’s pharmacy data.
The advancement in technology has offered the opportunity to assess medication adherence with electronic systems. A couple of devices have been developed or are in development to track medication use by patients. They comprise electronic pill bottle systems (also available for inhaled drugs), electronic blisters, mobile phone-based systems and ingestible electronic sensor systems.
The electronic pill bottle system links the pill bottle to a computerized system that monitors the use of drugs by the patient. Typically, a computer chip is placed inside of the pill bottle that is linked to a computerized system. Upon the opening of the pill bottle by the patient to pick up the pill, the date and exact time of the bottle opening is recorded. Thus, this system provides continuous data on the use of drugs by the patient. Some electronic bottle systems are designated to monitor adherence for patients using one drug. One of the most popular of this kind of device is the Medication Events Monitoring System (MEMSTM). Other devices have been designed to monitor adherence for those patients using multiple drugs. Such devices are made of multiple compartments in which drugs from different types are stored. From the electronic pill bottle system, the GlowCapTM is a more sophisticated device that uses a wireless system to send alerts to patients’ caregivers when the bottle is opened. It also provides monthly adherence reports that are sent to the patients’ caregivers. Limitations of electronic pill bottle systems include the high cost, the inability to record the number of drugs picked from the bottle and the inability to monitor the effective ingestion of the pill by the patient.
Electronic blisters are made with electronic sensors that allow recording the date and time of the drug removal from the blister. Electronic blisters have the advantage to deal with the inability of the electronic bottle system to monitor the number of pills removed from the bottle. An example is the Intelligent Drug Administration SystemTM. As with electronic bottle systems, the ingestion of drugs removed from the blister is impossible to monitor with electronic blister systems.
A newer electronic drug monitoring system is the ingestible electronic sensor, developed to deal with monitoring the ingestion of drugs removed from the electronic pill bottle. With this system, an ingestible micro-electronic sensor is incorporated in the pill. After ingestion, the sensor is separated from the pill in the stomach. Contact with the gastric fluid in the stomach activates the sensor that sends a signal to a skin patch monitor. The sensor is then eliminated with the stools. TheIngestion Event MarkerTM (IEM) is an example of such system. The cost of the system and the problem of acceptability may be important factors limiting its use by ambulatory patients. However, it presents real potential for use in clinical trials where there is a need to closely monitor treatment adherence to establish drug efficacy and safety. This system also presents a potential for use for diseases, like tuberculosis, that require a direct observation of the patient taking his medications.
Other developments of medication adherence assessment with electronic systems include video-based observations. With this system, patients have to make video when taking their drugs and then send the video to their caregivers via a mobile phone.
Future studies should target the development of devices to monitor adherence to injectable solutions, liquid medications and topical ointments since devices that monitor adherence to these categories of treatment are lacking. In order to get the full benefit of technology in assessing the degree of drug compliance by patients, strategies to improve acceptability of electronic systems in monitoring drug use and to promote wide use (by reduction of costs) are essential.
References:
Haynes, R., B.; Taylor, D., W.; Sackett, D., L.: Compliance in health care. Johns Hopkins University Press, 1979, 516
World Health Organization (WHO): Adherence to long-term therapies: Evidence for action. WHO Library Cataloguing-in-Publication Data, 2003, 209
Osterberg L. and Blaschke T.: Adherence to medication. The New England Journal of Medicine, 2005, Vol. 353 (5) 487-97.
Park L. G., Howie-Esquivel J., and Dracup K.: Electronic Measurement of Medication Adherence. Western Journal of Nursing Research, 2015, Vol. 37(1) 28–49
Vitality: GlowcapTM. Available through http://www.vitality.net/docs/pharma_presentation.pdf (accessed 27 June 2015)
DiCarlo, L. A.: Role for direct electronic verification of pharmaceutical ingestion in pharmaceutical development. Contemporary Clinical Trials, 2012; Vol. 33, 593-600.
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