Table 2.

Summary of study outcomes.

QUANTITATIVE STUDIES
STUDY	PRIMARY OUTCOME MEASURES	RESULTS	SECONDARY OUTCOME MEASURES	FINDINGS
Aftab et al., (2018) (1)	Diabetes control	Significant reduction diabetes in control (p = .03)
	General health status	Significant reduction on the mental subscale of the SF-36 from baseline to 60-week follow-up (p = .02)
	Serious mental illness symptoms	No significant reduction in depression or psychopathology
	Functioning	Significant reduction in functioning (p = .037). No significant reduction in disability
Chwastiak et al., (2018) (2)	Diabetes control	Improved diabetes control from baseline to 3-month follow-up (p = .049)
	BMI	Reduced BMI from baseline to 3-month follow-up (p = .04)
	Serious mental illness symptoms	No significant changes in measures of psychiatric symptoms
McKibbin et al., (2010) (3)	Diabetes control General health status	No significant change in diabetes control No significant change in BMI	Adverse events	2 participants did not complete the follow-up assessment due to inpatient hospitalisation
		Significant reduction on the physical symptoms subscale of the SF-12 from baseline to 16-week follow-up (p = .05).
	Serious mental illness symptoms	No significant change on the mental health subscale.
		Significant reduction in depression symptoms from baseline to 16-week follow-up (p = .01). No significant change in measures of psychiatric symptom severity Significant improvement in functioning from baseline to 16-week follow-up (p = .01). No significant reduction in disability rating (p = .06)
	Functioning
Sajatovic et al., (2011) (4)	Diabetes control	No significant change in diabetes control
	General health status	No significant change in general health status or BMI
	Serious mental illness symptoms	Significant reduction in depression (p = .01) and psychopathy (p = .01) at 16-week follow-up. No significant change in psychiatric symptom severity
	Functioning	Significant reduction in functioning (p = .01) and no significant reduction in disability (p = .06)
Sajatovic et al., (2017) (5)	Diabetes control	No significant change in diabetes control	Adverse events	119 adverse events among 74 participants. Adverse events occurred among 6 peer educators, 30 participants receiving treatment as usual, and 38 TTIM participants. There were three deaths (TTIM, n = 2; treatment as usual, n = 1).
	General health status	No significant change in general health status or BMI
	Serious mental illness symptoms	Significant reduction in psychopathy (p < 001) and depression (p = .016) from baseline to 60-week follow-up. No significant reduction in psychiatric symptom severity.
	Functioning	No significant reduction in disability ratings. Significant reduction in disability from baseline to 60-week follow-up (p = .003)
QUALITATIVE STUDIES
STUDY	THEMES	FINDINGS	SECONDARY OUTCOMES	FINDINGS
Blixen et al., (2014) (6)	Positive group experience	Delivering the intervention increased peer educators’ confidence and created group cohesiveness
	Success with learning the manual	Peer educators had a positive experience learning the training manual content
	Increased knowledge of T2D/SMI	Peer educators developed a greater understanding of their health conditions
	Improved self-management of T2D/SMI	Becoming a peer educator increased awareness of the importance of effective self-management
	Increased self-confidence	Becoming a peer educator increased confidence in knowing their role and supporting group members
	United in purpose	All group members had the same goal
Lawless et al., (2016) (7)	Disseminating health information	Good attendance from study participants Positive experience delivering the intervention	Participant attendance	80 (80%) participants attended at least one session, 49 (61%) completed all 12 sessions
	Facilitating group processes	Nurse educators encouraged the development of a therapeutic environment	Adverse events	Peer educators’ illness severity, participants’ symptoms impacting some group interactions
	Minimising logistical barriers	Peer educators used effective modelling strategies Nurse educators used various strategies to overcome logistical barriers encourage attendance
	Coordinating interdisciplinary communication	Nurse educators provided care-linkage to enhance communication between participants’ healthcare providers

Key: BMI = Body Mass Index; TTIM = Targeted Training in Illness Management.