Adherence and health care costs

Figures & data

Table 1 Methods of measuring adherence

Methods	Data source	Definition
Indirect measurements used in research and administrative settings
MPR*	Pharmacy claims	= (total days supplied)/(number of days between the first and last refills)
PDC*	Pharmacy claims	= (total days supplied)/(number of days in refill interval)
Indirect measurements used in patient care settings
Self-report	Patient	Patient recalls medications taken in response to care team query
Questionnaire	Provider	Use of validated tool for adherence markers
Pill counting	Provider	Staff member reviews patient supply for doses remaining
Dose counting device	Device	Device includes electronic or manual counter that tracks doses released
Electronic-prescribing	PBM interface	Reports transmitted from a pharmacy benefit manager to provider usually via EMR link
Direct measurement
Direct observation	Provider	Patient receives and takes medication at health care facility
Drug levels and markers	Laboratory	Patient blood or urine sample tested

Note:

* Generally not used in direct patient care.

Abbreviations: MPR, medication possession ratio; PDC, proportion of days covered; PBM, pharmacy benefit manager; EMR, electronic medical records.

Figure 1 Conceptual diagram displaying a mechanism that may contribute to the maintenance of the medication nonadherence problem within the US health care system.

Figure 2 Selected determinants of medication adherence.

Table 2 Selected strategies for improving medication adherence

Strategies	Examples
Patient
Education	Patient counseling by physicians or other health care personnel^Citation58
Engage social network	Family members can provide reminders and feedback. This is particularly helpful for patients with psychiatric disease^Citation85
Reminders	Automated alerts, telemonitoring^Citation86
Provider
Improve relationship with patients	Training physicians to improve their communication skills, patient activation by improving patient–physician communication^Citation87
External factors
Simpler regimen	Medications with long half-life or extended release^Citation9
Auto-delivery systems	Eg, auto-injectors, pumps^Citation89
EMR based	Electronic prescribing^Citation81
Team based care, care coordination	Patient centered medical homes; case management; engagement of nursing staff, pharmacists^Citation58
Value based insurance designs	Lowering copayments can improve adherence^Citation34

Abbreviation: EMR, electronic medical records.

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