METHODS OF MEASURING MEDICATION USE/COMPLIANCE IN THE COMMUNITY DWELLING POPULATION OF OLDER PEOPLE
Electronic Medication Monitoring Devices
Electronic medication monitoring devices use microchip technology to record and download data to a computer for review and analysis describing the actual date and time that a dose is removed from a container. Although the devices are recognized as the “gold standard” of compliance assessment, the method has drawbacks similar to the pill count method and the pharmacy refill method—electronic medication monitoring devices cannot assure that a dose that was removed was actually consumed or administered correctly (APhA, 2003). In addition to errors introduced when a bottle is opened and no medication is taken, errors may be introduced when a patient removes two doses during one opening (one for the morning and one for the afternoon) and only one event gets recorded for two doses taken (Samet, Sullivan, Traphagen, and Ickovics, 2001). Despite these limitations, electronically measured adherence has been more highly associated with clinical outcomes than self-report (Liu et al., 2001) and pill counts (Namkoong, Farren, O’Connor, and O’Mally, 1999).
Dunbar-Jacob et al. (2003) measured medication compliance by 169 community dwelling individuals age 62 and older (mean age = 70.7, range = 62 to 94) who had cardiovascular conditions in addition to other diagnoses for which medication use was monitored. Subjects were recruited from a heart failure clinic, from specialty practices in rheumatology, and through speaking to senior citizen groups in several small towns. Medication adherence (percentage of doses taken, percentage of days with the correct number of doses, and the percentage of expected doses within the correct timing interval) for three groups of patients was monitored: medications prescribed for a community sample of subjects with cardiovascular problems, medications prescribed for a clinic group of patients with heart failure, and medications for a clinic group of patients with rheumatoid arthritis. Adherence was measured with the ARDEX Medication Event Monitoring System that uses a medication bottle cap fitted with a microprocessor to capture the timing (date and time) of each medication-taking event. When the bottle is opened, the microprocessor records the date and time, and downloads the data to an ASCII file for analysis.
Sociodemographic factors included in the study to determine their ability to predict medication adherence were: gender, age, race, marital status, education, number of people living in the household, employment status, household income, insurance status for medications, and frequency of daily dosing for the medication being monitored. Sociodemographic data were pooled across the three medication study groups in the analysis.
Adherence values showed that on average, across the three groups, 89 percent of the prescribed doses were taken, the correct number of doses taken was taken on 76 percent of the days, and 64 percent of the doses were taken within the correct timing interval. When comparing groups, the subjects with rheumatoid arthritis exhibited the lowest adherence levels for each of the three adherence measures (77% for prescribed doses taken, 59% for days with the correct number of doses taken, and 44% for doses taken within the correct timing interval). The community group with cardiovascular problems and the heart failure group had similar adherence levels, with the heart failure group showing a slightly higher percentage of doses taken than the community group with cardiovascular problems (98% compared to 90%) and a higher percentage of days with the correct number of doses (87% compared to 82%). The community group had a higher percentage of doses in the correct timing interval when compared to the heart failure group (73% compared to 72%).