A Systematic Analysis of Reviews Exploring the Scope, Validity, and Reporting of Patient-Reported Outcomes Measures of Medication Adherence in Type 2 Diabetes

Figures & data

Figure 1 Flow chart of the review assessment framework.

Abbreviations: PROM, patient-reported outcome measure; MA, medication adherence; SR, systematic review; COSMIN, COnsensus-based Standards for the selection of health status Measurement Instruments.

Figure 2 PRISMA 2020 flow diagram.

Notes: *From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. doi: 10.1136/bmj.n71. For more information, visit: http://www.prisma-statement.org/.

Table 1 Quantitative Characteristics of Included Systematic Reviews

Systematic Review Number	Title	Search Period	Publication Year	Number of Included Studies	Number of T2DM PROM Studies	Number of MA PROMs
1	Adherence to diabetes medication: a systematic review^Citation34	2004–2013	2015	27	18	11
2	Medication Adherence with Diabetes Medication: A Systematic Review of the Literature^Citation25	2007–2014	2016	98	31	17
3	Accuracy of a screening tool for medication adherence: A systematic review and meta-analysis of the Morisky Medication Adherence Scale-8^Citation19	2008–2015	2017	28	9	4
4	A systematic review of patient-reported and economic outcomes: value to stakeholders in the decision-making process in patients with type 2 diabetes mellitus^Citation35	1996–2010	2011	185	7	5
5	Medication taking and diabetes: a systematic review of the literature^Citation28	1990–2007	2007	36	1	1
6	Factors associated with medication adherence among patients with diabetes in the Middle East and North Africa region: A systematic mixed studies review^Citation36	Database origin-2016	2017	30	14	6
7	The Consequences of General Medication Beliefs Measured by the Beliefs about Medicine Questionnaire on Medication Adherence: A Systematic Review^Citation42	1999–2019	2020	11	5	4
8	Improving the adherence of type 2 diabetes mellitus patients with pharmacy care: a systematic review of randomized controlled trials^Citation43	Database origin-2013	2014	6	4	3
9	A systematic literature review of methodologies used to assess medication adherence in patients with diabetes^Citation37	2007–2013	2014	59	15	9
10	Self-Efficacy and Diabetes Self-Management in Middle-Aged and Older Adults in the United States: A Systematic Review^Citation26	1990–2018	2020	11	5	5
11	Effective interventions to improve medication adherence in Type 2 diabetes: a systematic review^Citation27	2000–2013	2014	27	12	8
12	Evaluation of the Measurement Properties of Self-reported Medication Adherence Instruments Among People at Risk for Metabolic Syndrome: A Systematic Review^Citation22	Database origin-2015	2016	32	11	10
13	Medication adherence among diabetic patients in developing countries: Review of studies^Citation24	2000–2018	2020	57	16	13
14	Systematic review of pharmacist interventions to improve adherence to oral antidiabetic medications in people with type 2 diabetes^Citation44	Database origin-2011	2012	8	2	2
15	A Review of Pharmacist-led Interventions on Diabetes Outcomes: An Observational Analysis to Explore Diabetes Care Opportunities for Pharmacists^Citation45	2012–2018	2019	25	5	3
16	The association between the measurement of adherence to anti-diabetes medicine and the HbA1c^Citation46	Database origin-2013	2014	23	4	5
17	A systematic review and meta-analysis of non-adherence to anti-diabetic medication: Evidence from low- and middle-income countries^Citation38	2000–2019	2020	43	26	19
18	Measurement Properties of Existing Patient-Reported Outcome Measures on Medication Adherence: Systematic Review^Citation23	Database origin-2019	2020	214	35	31
19	Measurement Properties of Patient-Reported Outcome Measures for Diabetes: Systematic Review^Citation20	Database origin-2020	2021	363	21	20
Total				1283	241	228^a

Note: ^aAfter removal of duplicates, a total of 104 unique PROMs were identified (See Table 3).

Abbreviations: T2DM, type 2 diabetes mellitus; PROM, patient-reported outcome measure; MA, medication adherence.

Table 2 Qualitative Characteristics of Included Systematic Reviews

Systematic Review Number	Primary Outcome(s)	Secondary Outcome(s) (If Defined)	Medicines Included	Language(s) of Included Studies
1	Prevalence of adherence (%)	Factors associated with MA behaviours	OA +/- insulin	English
2	Risk factors associated with non-adherence, interventions that improve adherence and of non-adherence on glycaemia		OA +/- insulin	English
3	Psychometric properties and validity of MMAS-8		OA +/- insulin	English
4	Assess relationship between PROs and economic outcomes		OA +/- insulin	English, Spanish, French, Italian
5	Evidence of barriers to MA, interventions to improve MA (focus on educators and self-care)		OA +/- insulin	English
6	Rates and factors affecting MA in MENA region		OA +/- insulin	No limitations
7	Evaluate the impact of general medication beliefs (via BeMQ) on MA		OA +/- insulin	English
8	Evaluate effectiveness of pharmacist interventions on adherence for OA		OA	No limitations
9	Identify MA methods for OA +/- insulin	Identify specific methods for assessing insulin regimen MA	OA +/- insulin	Not defined
10	Examine association between self-efficacy and diabetes self-management in middle-aged and older adults	Does the association apply across races and ethnicities	OA +/- insulin	Not defined - US reported studies hence assumed English only
11	Identify interventions to improve medication adherence in T2DM and their efficacy	Identify areas for future research based on the review outcomes	OA +/- insulin	English
12	Identify the measurement properties of PROMs MA in patients at risk for metabolic syndrome		OA +/- insulin	English
13	Evaluate interventions on medication adherence on DM in developing countries		OA +/- insulin	Not defined
14	Describe pharmacist interventions to improve adherence to OA medicines	Identifying the role of health behaviour theory in the development of interventions	OA	No limitations
15	Evaluate effectiveness of pharmacists’ interventions on clinical outcomes and prevention of complications in diabetes mellitus		OA +/- insulin	English
16	To examine the relationship between adherence and glycaemic control and the effect of the measurement type on this relationship		OA +/- insulin	English
17	Summarise evidence of medication adherence and associated factors in LMIC		OA +/- insulin	Not defined
18	Summarise the psychometric properties of PROMs for MA	Assess the quality of the evidence	OA +/- insulin	English
19	Identify psychometric properties of PROMs validated for Type 2 Diabetes		OA +/- insulin	English

Abbreviations: OA, oral antiglycaemic; MA, medication adherence; MMAS-8, Morisky Medication Adherence Scale 8-item; BeMQ, Beliefs about Medicines Questionnaire; PRO, patient-reported outcome; PROM, patient-reported outcome measure; MENA, Middle East and North Africa; T2DM, type 2 diabetes mellitus; DM, diabetes mellitus; LMIC, low and middle income countries.

Table 3 Reporting Assessment of PROMs

Number	No. Studies (n)	Studies Below Reporting Standard (n,%)	Exclusion Reasons (n)
1	18	3 (16.7)	Taxonomy^a (3)
2	31	19 (61.3)	Taxonomy (17)
			Tool reported not used in study (1)
			Incorrect tool reported (1)
3	9	6 (66.7)	Described but not referenced (6)
4	7	5 (71.4)	Taxonomy (5)
5	1	1 (100.0)	PROM not declared (1)
6	14	11 (78.6)	Taxonomy (8)
			Described but not referenced (1)
			Incorrect tool reported (1)
			Tool reported not used in study (1)
7	5	5 (80.0)	Taxonomy (3)
			Described but not referenced (2)
8	4	2 (50.0)	PROM not declared (2)
9	15	7 (46.7)	Taxonomy (6)
			Incorrect tool reported (1)
10	5	2 (40.0)	Incorrect tool reported (1)
			Taxonomy (1)
11	12	8 (66.7)	Taxonomy (6)
			Incorrect tool reported (1)
			Tool reported not used in the study (1)
12	11	0
13	16	8 (50.0)	Incorrect tool reported (2)
			Taxonomy (6)
14	2	2 (100.0)	Taxonomy (2)
15	5	2 (40.0)	PROM not declared (2)
16	4	3 (75.0)	Taxonomy (3)
17	26	28 (107.7)^b	Taxonomy (24)
			Incorrect tool reported (2)
			PROM not declared (2)
18	35	2 (5.7)	Incorrect tool reported (2)
19	21	0

Notes: ^aTaxonomical issues included cases where either the target language was not defined if different from the original PRO, or if no distinction had been made between adaptations of a PROM; ^bSome studies reported >1 eligible PROM and hence could potentially exceed 100.0%.

Abbreviation: PROM, patient reported outcome measure.

Figure 3 Systematic review assessment criteria.

Notes: The COSMIN criteria were introduced in 2010, which excluded one systematic review from the analysis due to its publication prior to 2010, hence n = 18 for this sample. A total sample of n = 19 was used to assess the other criteria included in this figure.

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