Table 1.

Different types of qualitative and quantitative tools used to measure adherence to treatment

Qualitative (subjective) measures

Quantitative (objective) measures

• Self-report using MMAS-4 or -8a • Self-report using other standardized questionnaires or surveys, such as SDSCA or MARS • Patient-reported subjective assessment of adherence (eg, in response to a simple, nonjudgmental question from the health care provider, such as “How often do you miss taking your medication?”) • Provider-reported subjective assessment of adherence (eg, based on clinical response and/or laboratory results, such as HbA1c) • Patient diaries or computerized logbooks • Mobile phone real-time assessment

• MPRb (or variations of MPR, such as PDCc), usually assessed using pharmacy-claim databases • Pill counts • Electronic monitoring devices (eg, MEMS) • Biochemical measurement using nontoxic biological marker • Measurement of concentrations of a drug or its metabolite in blood or urine

Notes:

^aProvide an adherence score by summing responses (yes = 0, no = 1) to MMAS items; higher scores indicate better adherence.¹⁶

^bNumber of days of medication supplied within prescription-refill period divided by number of days in refill period.¹⁶,¹⁹

^cNumber of days with drug on hand divided by number of days in specified time interval.⁸³ Data from these studies.⁴,¹⁰,¹²,¹⁴,¹⁵,¹⁷,¹⁸

Abbreviations: HbA_1c, glycosylated hemoglobin; MARS, Medication Adherence Report Scale; MEMS, medication event-monitoring system; MMAS, Morisky Medication Adherence Scale; MPR, medication-possession ratio; PDC, proportion of days covered; SDSCA, Summary of Diabetes Self-Care Activities. Adherence to antihyperglycemic medication