Table 2.

Summary of outcome measures.

Outcome measures			Definition	Reference(s)
Medication adherence (N=19)
	Continuous, multiple-interval measures of medication acquisition (CMA)	CMA is the sum of days of medication supply obtained divided by the total number of days of study participation [27,53,54].			[44]
	Proportion of days medication covered (PDC)	PDC measures the persistence to the medication therapy by calculating the total days’ supply divided by the number of days of study participation. The value is capped at 100% [27]. It is a common proxy-measure of adherence.			[32,34,45,47]
	Continuous measure of medication gaps	This measure refers to the total number of treatment gap days divided by the duration of the time period of interest. It indicates the proportion of time for which patients do not have drug exposure [53].			[44]
	Medication possession ratio (MPR)	MPR is the proportion of days’ medication supply obtained over either refill interval or fixed refill [53]. MPR is calculated for the individual patient and can create different denominators.			[45]
	Eight-item Morisky Medication Adherence Scale (MMAS-8)	MMAS-8 is a validated medication adherence scale that contains 7 Yes/No responses and a 5-point Likert response [53]. The scale captures patients’ medication-taking behavior and barriers to adherence.			[35,37]
	Pill count	Pill count is the number of consumed pills divided by the number of total prescribed pills [53].			[37]
	Measurement cutoff	This measure requires setting an arbitrary cutoff value to a continuous measure for identifying adherence and nonadherence into dichotomous outcomes [53,55]. It is typically less sensitive than the original measure [55]. For instance, taking medication with 80% cutoff of a 28-day medication cycle, or PDC with 80% or above.			[2,32,40,49]
	Measures involving electronic medication devices	Electronic medication devices aim to record adherence performance for analysis. Typical features include recording dosing events, audio/visual reminders, electronic displays, and monitoring and feedback on adherence performance. However, not all features are available in all devices. In many medication adherence studies, the MEMS is commonly used [53].			[36,40,42,51,52]
	Other questionnaires and scales	These questionnaires and scales are generally validated against other conditions and related measures to assess medication regime conditions for a broad range of diseased populations [53] or specific ones. Heart failure compliance scale and validated diabetes mellitus regimen adherence scale (Edwards Scale) are some examples. Self-report questionnaires are also included.			[3,31,32,39,43]
	Unspecified	Medication adherence measure was not specified.			[38]
Health care outcome measures (N=11)
	Adverse event	Measures refer to the number of emergency visits or instances of hospitalization or untoward medical occurrence.			[38,43]
	Quality of life	Various measures may apply, including Short Form-36/Short Form-12 Physical Component Scale and Mental Component Scale, Asthma-Related Quality of Life, and (Pediatric) Asthma Quality of Life Questionnaire.			[41,42,48,50]
	Patient satisfaction	This measure refers to how well eHealth met patient expectations. Various measures may apply, including the 8-item Client Satisfaction Questionnaire and the patient satisfaction survey.			[32,41,43,49]
	Health spending	Various measures may apply, including assessing monthly or yearly expenditure via claims data, and medical cost computed by direct and indirect outpatient and inpatient cost items.			[33,34,46]