This review focused exclusively on electronic monitors of medication adherence in use across pediatric populations and updates the review provided by Quittner et al (8
). As such, it provides an important resource regarding strengths and weaknesses of particular electronic monitors in several pediatric disease groups. These data are especially relevant for individuals considering incorporation of these devices into research protocols or clinical practice. There are several advantages inherent in electronic monitors, which is likely responsible for their increased use and frequent reference as the “gold standard” to which other measures of adherence (e.g., pill count, self-report) are compared (e.g., (9
)). Clinicians can use electronic monitors with their patients to address a number of clinical issues and initiatives. These may include, among others, 1) dosing regimen complexity (e.g., multiple doses per day may be too difficult for some patients), 2) dose timing, which can affect drug concentration in blood, 3) white coat compliance or other problematic patterns of medication taking, and 4) ongoing objective monitoring of adherence behavior, which is superior to current practice habits which rely on self-report, clinician ratings, or perhaps no assessment. In conjunction with continuing advancements in software development, electronic monitors enable insight into medication taking patterns (e.g., white coat compliance, drug holidays), help identify barriers to medication adherence, and are sensitive to treatment effects (e.g., (25
)). These features allow for testing of various hypotheses regarding adherence patterns, which is critical to ultimately designing and optimizing interventions to promote treatment adherence.
However, electronic monitors are not without their limitations. Difficulties related to mechanical malfunctions are evident across all electronic monitors. In addition, the high cost and training necessary to effectively use current monitors cannot be understated and restricts their use in primary or specialized clinical care. However, as additional data regarding the relationship between monitoring, adherence, and health outcomes emerges, health management organizations and other insurance companies may be more likely to assume their cost. Similar to other adherence measures (e.g., serum assays, self-report), inability to confirm the number of medications ingested restricts their reliability and validity. Use of monitors that include feedback (e.g., Trackcap) and introduction of novel devices (e.g., unfamiliar pill container) into the family routine also limit their function as naturalistic measures. Consequently, this review supports previous recommendations for inclusion of other methods of adherence measurement (e.g., serum assay, pill count, self-report) to complement electronic data (8
). Although review of these other methods goes beyond the scope of the current review, previous research suggests that the use of these measures also incorporates particular strengths/weaknesses.
Regarding specific recommendations in selecting monitors for future research and/or clinical use, several conclusions can be drawn. Despite the tremendous potential offered by newer devices, available studies strongly support the reliability and validity of MEMS as the electronic device of choice in monitoring oral medication adherence. Future, additional data for other oral medication monitors will better allow investigators/clinicians to make informed decisions regarding their use. Concerning inhaled medication monitors, the MDILog and Doser have been widely used in pediatric asthma. Given their similar strengths and weaknesses, individuals are encouraged to examine the needs of their study and/or clinical practice and weigh the advantages/disadvantages of each monitor in best meeting their requirements. Finally, that the I-neb AAD system has been redesigned to address some of the weaknesses in its earlier model should be encouraging in measuring nebulized medication adherence.
Although this review summarizes available data regarding electronic adherence measures and their use in pediatric disease groups, these data are meant to suggest some issues that may be encountered when using these devices, not to dissuade researchers or clinicians from any particular device. Of note, many of the studies included in this review relied on small samples, and/or were pilot studies. Studies varied widely in regard to the information provided concerning device function. For example, even though validation data may be available in adult studies, data was not always provided for the pediatric population. Standardization of such data provided in future studies will help further advance research in this area. In addition, some of the measures are not currently available or have been updated to address earlier technological issues. However, given the small number of articles, they were still included to illustrate possible difficulties that may arise. It is anticipated that the information provided in this review will aid individuals in selecting appropriate electronic adherence monitors for research and/or clinical purposes and effectively address potential weaknesses of measures through careful planning and monitoring.
Despite these limitations, this review provides several key directions for future research and development in this area. First, improvements in technology will increase electronic adherence measures’ reliability and validity and may help to decrease their cost. Second, use of a cellular device signal will enable remote downloading and relieve the burden associated with home visits or downloading at clinic appointments. Several companies are developing and testing these technologies now. Third, research and clinic friendly servers that enable direct downloading and interpretation of data will enhance their usefulness for analysis and efficient incorporation into routine clinical visits. For example, clinicians can use electronic monitoring data to identify and problem-solve with families around possible adherence-related difficulties at the time of clinic visits. Fourth, patient-friendly devices (e.g., pill boxes that hold a full week of medication doses, portable devices) will help to foster their acceptability to families. Finally, investigation of how best to combine measures of adherence is imperative across chronic conditions. For example, researchers have used correction factors or composite scores calculated from electronic adherence measures to address inflation in self-report and pill count data (e.g., (38
)). With advances in medicine, the continued awareness of adherence as a significant health care issue in pediatric populations, and demonstrated relationships between adherence and health outcomes (e.g., (15
)), the use of electronic monitors may become a permanent fixture in adherence-related research and clinical practice.