Table 2.

ADHERENCE ASSESSMENT METHOD	EXPLANATION OF METHOD	ADVANTAGES AND DISADVANTAGES	REFERENCE
Healthcare provider interviews	consists of healthcare providers’ asking patients in a face-to-face manner or by telephone whether they had taken their oral chemotherapy	Advantages: less expensive; integrated into patient care; allows for more detailed understanding of adherence issues Disadvantages: accuracy of information less clear (patients embarrassed and will not confess to poor adherence); healthcare provider may forget to ask	5, 6, 7, 8, 9
Patient-reported adherence with diaries or calendars	patients report their pill taking after each dose or at some other frequency	Advantages: low cost; accuracy of information might vary based on patients’ understanding of who would get the report (healthcare provider or personnel within a large data base) Disadvantages: patients may forget to complete or may do so less frequently with gaps in accuracy; diaries/calenders can get lost leaving large gaps in data	7, 8, 9, 10, 11, 12, 13, 14
Patient-completion of adherence scales	patients complete a questionnaire that estimates their understanding of adherence and frequency of medication adherence	Advantages: low cost; less effort intensive for the patient than diaries; sometimes allows for better understanding of why adherence might be poor(drug side effects, drug expense, etc) Disadvantages: accuracy of data may be an issue (patients embarrassed about poor adherence); patients may lose questionnaire prior to submission or may not complete; requires higher degree of patient literacy than a diary or calender	15, 16
Medication Event Monitoring System(MEMS)	an electronic cap that covers the medication bottle activates every time the bottle is opened and counts and records patients’ opening the cap as taking their medication	Advantages: relieves burden from patients of recording adherence Disadvantages: more expensive than other methods; patients might find it intrusive; risk of malfunction; may suggest over-adherence, as any time the bottle is opened, it counts as a pill ingestion	12, 13, 14, 17, 18, 19, 20
Automated Voice Response System	patients are called at the times of their choice, respond to questions with their telephone touch pad, and an automated phone response system provides information specific to each patients’ tailored informational needs relevant to drug adherence	Advantages:provides tailored information on adherence; more accessible to patients as a result of wide-spread cell phone use; high patient acceptance; capable of real time detection of over-adherence. Disadvantages: more expensive; may not be able to be tailored to address every single patients’ needs	21
Drug and Drug Metabolite Assays	patients submit their urine, blood, or hair for drug level assessment	Advantages: provides objective information Disadvantages: expensive; may miss sporadic skipping of medication or timing of medication administration; may not be able to detect small changes in adherence; patients might find it intrusive or painful (blood draw); does not take into account pharmacogenomics differences from patient-to-patient in drug bioavailability or metabolism; not amenable to monitoring all oral agents	9, 22, 23
Databases that Capture Prescriptions	Either hospital-based pharmacy or other such databases are used to examine drug adherence based on the number of prescriptions filled.	Advantages: little/no effort on the part of the patient; might lessen Hawthorne effect; might be lower cost (depending on infrastructure in place) Disadvantages: patients may fill prescriptions elsewhere and therefore good adherence may not be registered; might be a great delay between knowing about adherence and assessing other outcomes, depending on the organization of the data base	2, 11, 16