What We Know About the Peer Workforce and Economic Evaluation for Peer Recovery Support Services: A Systematic Review

Abstract

Background:

Peer recovery support services (PRSS) for substance use disorder (SUD) have expanded in the past 2 decades to be formally certified and reimbursed under Medicaid in almost every US state. This rapid expansion has been followed by a growth in research, but 2 persistent gaps remain: a lack of research on the peer workforce, and a lack of economic evaluation research. This systematic review examines the current literature on PRSS to summarize what is currently known about the SUD peer workforce and collect potential PRSS economic evaluation parameters, and clearly identify the current gaps in each category.

Methods:

PRISMA methods were followed and a PROSPERO protocol was registered (CRD42022323516). The search included a database search of peer-reviewed journal articles and dissertations, and also a hand-search of conference presentations and evaluation reports. Manuscripts were categorized as either workforce development-related and/or those containing potential economic evaluation parameters.

Results:

Forty-two total manuscripts were included, with 22 related to the peer workforce and 26 containing potential economic evaluation parameters. Manuscripts with workforce-related findings covered peer worker characteristics, characteristics of PRSS delivery, or peer worker training-related outcomes. Economic evaluation parameters were primarily costs related to service utilization patters with some limited reporting on peer worker pay, as well as multiple sources that can be used to estimate averted medical costs. Effectiveness parameters were primarily substance use related, as virtually all quality of life and life functioning parameters are not readily convertible to estimating quality-adjusted life years.

Conclusion:

Future PRSS research can contribute to filling these gaps in the evidence base by addressing remaining questions about the interrelationship between peer worker job satisfaction, job tenure, and patient outcomes, as well as by using more consistent outcome measures, especially in the realm of quality of life and life functioning.

Introduction

The informal practice of individuals in substance use disorder (SUD) recovery helping others seeking recovery from SUD has an established history in the United States.^1,2 Formalizing this practice by recruiting, training, and certifying peer workers at the state level began first for mental health peer workers in the late 1990s, followed by SUD peer workers in the early 2010s.³ Today, at least 37 states certify SUD peer workers to provide Medicaid-reimbursable peer recovery support services (PRSS).⁴

Previous systematic reviews of PRSS have identified a variety of settings in which peer workers deliver services of varying durations and intensities.^5–7 Although the moderate evidence base for the effectiveness of PRSS is growing and suggests improved recovery outcomes compared to controls, the variability of practices highlights challenges to meta-analyses,^5–7 despite which PRSS have been increasingly adopted across US states.⁸

Research on the peer workforce is more developed for mental health peer workers compared to SUD peer workers and suggests that low pay and limited career advancement opportunities are factors behind peer workers leaving the field to pursue other careers.⁹ Difficulties with integration into care teams, lack of role clarity, and on-the-job discrimination experiences contribute to peer worker attrition.^3,9,10 Clearer understanding of factors like peer worker scopes of practice, compensation, and service delivery patterns for the peer workforce can also contribute to the closing of a second gap on PRSS research identified in previous systematic reviews—a lack of economic evaluations of PRSS^5,6—because such information about the peer workforce also forms key model inputs for economic evaluation methods like cost-effectiveness analysis.^11,12 The gray literature may hold potential cost and effectiveness parameters including reimbursement rates across the United States.^13,14 Because PRSS are implemented across a variety of settings and durations, modeling PRSS for economic evaluations may be more challenging compared to manualized interventions like Screening Brief Intervention and Referral to Treatment (eg, Madras et al¹⁵). Previous systematic reviews of PRSS have summarized PRSS participant-level outcomes, which are a key part of economic evaluation (ie, effects in a cost-effectiveness analysis or benefits in a cost–benefit analysis), but have not highlighted what economic evaluation parameters remain missing from the literature, hindering these evaluations. Such evaluations are needed for key stakeholders—including funders and policymakers, as well as people with SUD accessing and providing these services¹⁵—to assess the efficiency of PRSS and further encourage PRSS expansion.

Future research on PRSS could benefit from a clearer definition of these 2 existing gaps in the literature, and because findings related to the peer workforce could also serve as economic evaluation parameters (eg, reimbursement or compensation patterns), then a single review with 2 overlapping foci is warranted. Previous literature reviews have focused primarily on reviewing the evidence of the effectiveness of PRSS across settings and populations.^5–7 The objective of the present study is to systematically review and describe the literature related to (1) the PRSS workforce and related to (2) identifying cost and effectiveness parameters for use in future economic evaluations of PRSS.

Methods

This systematic review was developed following PRISMA guidelines for reporting systematic reviews and includes a completed PRISMA flow diagram as Figure 1. The search protocol was registered in PROSPERO (CRD420223235 16). The search included a search of databases of peer-reviewed materials (Embase, Medline Ovid, PsycINFO, and PubMed; March 4, 2022), a dissertation database (ProQuest; May 19, 2022), and a hand-search of the gray literature including conference presentations and reports.

Figure 1.

PRISMA flow diagram.

Inclusion Criteria

Included materials were limited to publications in English and studies conducted in the United States, as both workforce and economic studies will be particular to national conditions. Included studies were further limited to only those involving state-credentialed peer workers: studies of informal peer support or the provision of only a study-specific intervention were excluded, as were studies of mental health peer support. Only studies published in 1999 or later were included, as state-level certification of peer workers in the United States began that year.⁸ Table 1 provides a summary of inclusion and exclusion criteria.

Table 1.

Inclusion and Exclusion Criteria.

Type	Criteria
Inclusion	• English language
	• Study or evaluation conducted in the United States
	• Publication date of 1999–2022
	• Presents results (not descriptive only) or cost parameters
	• Peer workers addressing substance use disorder or problematic substance use, or dually diagnosed patients, but with an emphasis on substance use
	• Findings related to the peer workforce and/or that can be used as parameters in an economic evaluation
Exclusion	• Peers delivering services are not certified (by a US state certification board or similar) peer workers, or are informal social support (eg, participants in a mutual aid group)
	• Primary mental health focus
	• Primary focus of support not related to substance use (eg, housing)
	• Reviews

Search Strategy

The database searches used the following words and phrases: addiction, substance use disorder, alcohol use, drug use, substance use, alcohol abuse, drug abuse, substance abuse, alcohol misuse, drug misuse, substance misuse, peer, peer support, peer specialist, peer recovery, peer recovery coach, peer worker, peer workforce, recovery support, peer-based recovery support, recovery support service, workforce, peer mentor, and MeSH terms related to the health workforce. Specific economic evaluation methodological terms were not included because the existing search terms would have identified any such analyses in the literature because all such analyses would include a description of the PRSS intervention. The hand-search for conference presentations included abstracts from the College on Problems of Drug Dependence (2005–2022), American Public Health Association (2021–2022), and American Society of Addiction Medicine (2013–2021). The hand-search for reports began with known evaluation reports^13,16 and expanded iteratively to include reports cited in publications encountered in the database search, reports on websites related to PRSS, and by outreach to known and potential authors of evaluation reports related to PRSS.

Data Screening, Collection, and Synthesis Strategy

The first author (SCM) conducted all initial screening, JMW served as the second reviewer for manuscripts with workforce-related findings, and HSB served as the second reviewer for economic evaluation-relevant manuscripts. Inclusion decision discrepancies were resolved by consensus. Because all study types that contained some kind of finding (qualitative or quantitative findings accepted, but no descriptive papers or protocols) were eligible for inclusion, all outcomes were included if they were relevant to either of the search foci: workforce or economic evaluation parameters. Data extraction was conducted in Excel, and included extraction of all findings relevant to the 2 search foci. While risk of bias was qualitatively assessed by the review team (SCM, JMW, and HSB) for each report, bias is not reported here because all findings relevant to the search were ultimately included, and no meta-analysis was performed. Similarly, no certainty assessment was performed for this review. Instead, a narrative synthesis approach was used to describe findings within search foci categories.

Results

A summary of the 42 included manuscripts across the 2 categories are provided as Table 2, and Figure 1 contains a PRISMA flow diagram. Twenty-two manuscripts were identified that had findings related to the SUD peer workforce and 26 manuscripts had potential economic evaluation parameters. Common reasons for excluding manuscripts were as follows: did not involve trained and state certified SUD peer workers; protocol or descriptive manuscript (no findings); not in the United States.

Table 2.

Summary of Included Papers.

Authors (year)	Design	Setting	Workforce	Economic
Almeida et al (2020)	Multi-site qualitative study within a single US state interviewing peer workers (n = 15)	Integrated mental health and SUD service settings (3 sites)	Qualitative themes regarding (1) challenges peer workers face with role clarity and boundaries with participants; (2) recommendations for hiring peer workers	N/A
Anvari et al (2021)	Multi-site qualitative study across multiple US states interviewing peer workers (n = 15)	Multiple settings	Qualitative themes regarding COVID-19-related changes to PRSS provision, including some positive changes useful outside of the pandemic context	N/A
Ashford et al (2021)	Quasi-experimental, single group, 2 time points (n = 3459)	20 recovery community centers	N/A	Effects: Recurrences of substance use events. Change in recovery capital from baseline to latest available measure Costs: Service utilization patterns, ED visits
Beck et al (2018)	Cross-sectional, search of publicly available data	Entire US	Peer worker Medicaid reimbursement rates. Credentialing requirements. Authorized services	Costs: Peer worker Medicaid reimbursement rates as of 2018. Mean = $ 12.98per 15 minute increment, range = $5.75 to $24.49
Belenko et al (2021)	Randomized controlled trial (PRSS n = 39, control n = 37)	Drug court (Philadelphia Treatment Court)	N/A	Effects: Null effects on treatment engagement and substance use. Significant reduction in criminal legal system involvement. Higher drug court engagement Costs: Service utilization patterns for drug court PRSS participants
Byrne et al (2020)	Randomized controlled trial (PRSS n = 51, control = 47)	Hospital inpatient unit, South Carolina	N/A	Effects: Null findings for substance use, physical and mental health measures. Significantly higher engagement in recovery support services in PRSS group. Costs: Service utilization patterns.
Byrne et al (2022)	Multi-site qualitative study across multiple states with peer workers and other types of workers (n = 132)	Multidisciplinary mental health and substance use disorder services organizations (n = 5)	Themes drawn from the study include organizational commitment to embed peer work, organizational culture and strategies, effective recruitment strategies, potential impacts, and additional challenges	N/A
Castedo de Martell et al (2022)	Non-experimental, observational (n = 448)	Peer worker trainees in Texas	Peer worker trainee demographics and prevalence of training stage completion. Associations between personal and psychosocial variables and training outcomes	N/A
Chapman et al (2018)	Multi-site qualitative, comparative case study in 4 US states	Multiple settings	Describes settings, policy and advocacy environments, and funding environments in 4 example states	N/A
Collins-Pisano et al (2021)	Qualitative, focus groups (n = 59) recruiting participants from international peer worker email list	Focus group participants employed across multiple settings	Core competencies; (1) protecting service user rights; (2) technical knowledge and skills; (3) available technologies; (4) equity of access; (5) digital communication skills; (6) performance-based training; (7) monitoring digital peer support and addressing digital crisis; (8) peer support competencies; (9) self-care; (10) health literacy/digital health literacy	N/A
Collins et al (2019)	Single-site qualitative study including patients (n = 46) and providers (n = 12)	Single hospital in Oregon providing PRSS to hospitalized patients	Peer workers serve translational role between patient and clinical team, and have especially high trust with patients. While the peer worker role is a step toward career development, hospital setting is especially stressful	N/A
Cos et al (2020)	Quasi-experimental, single group, 2 time points (patients n = 305, 3 peer workers)	Federally Qualified Health Center in Northeast with PRSS program	Example protocol for long-term PRSS. Median peer worker salary ($34 000) and peer supervisor salary ($45 000) exclusive of benefits and other costs	Effects: Significant reduction in substance use. Improved PHQ-9 and GAD-7 scores, employment and monthly income. Slight but significant increase in criminal legal system involvement Costs: Peer worker pay. Service utilization. Reduction in hospitalizations
Fabiano et al (2019)	Non-experimental, descriptive (n = 150)	Emergency department	N/A	Effects: % agreeing to PRSS in ED, % engaged in recovery and linked to other services. Overdose mortality Costs: Rehospitalization
Faces & Voices of Recovery (2010)	Qualitative; report from an expert roundtable.	Multiple	(1) Guidance on typical service utilization, (2) Caseload recommendations, recommendations on qualification requirements, and service roles	(3) Guidance on typical length of service, and (4) Core competencies,
Gertner et al (2021)	Non-experimental, feasibility study (n = 1037)	Emergency department	N/A	Effects: Receipt of buprenorphine in ED Costs: Patient uninsured prevalence, peer worker screening rate and hours
Guenzel and Dai (2021)	Quasi-experimental, single group, 2 time points (n = 12 peer worker trainees)	American Indian peer worker training program	Post-training self-assessments significantly improved compared to pretraining self-assessments. Greatest improvement in PRSS activities and techniques	N/A
Hagaman (2021)	Cross-sectional (n = 565 peer workers)	Multiple settings across Appalachia	Peer worker demographics, life and recovery history characteristics. Recommendations for improving training. Working characteristics (settings, hours, pay, services delivered, advancement opportunities). Experiences of stigma and interpersonal work relationships. Job satisfaction and pay are significantly positively associated. Financial fragility among peer workers	Costs: Peer worker pay in Appalachia. Site and workforce tenure
Ham so et al (2013)	Single-site qualitative study (n = 10)	Methadone treatment program	Impact of being a peer worker on identity, future outlook, and relationship to own use of methadone	N/A
Hansen et al (2020)	Quasi-experimental, single group, 2 time points (n = 155 peer worker trainees)	Three recovery community organizations in Houston, TX	Peer worker demographics. Satisfaction with training. Durability of training satisfaction and perceptions of training usefulness to participants	N/A
Hymes (2015)	Qualitative study of current and former peer workers (n = 6) in one state at multiple sites	Multiple, single state (Virginia)	Peer worker motivations and path to employment. Career outlook and job stability. Professional and personal experiences during time as peer worker	N/A
Kawasaki et al (2019)	Non-experimental, descriptive	Pennsylvania hub and spoke system	Description of key peer worker role within a hub and spoke system	N/A
Kelley et al (2021)	Quasi-experimental, single group, 2 time points (n = 422 participants)	Multiple American Indian PRSS programs in Montana and Wyoming	N/A	Effects: Significant improvements in housing, school/training, employment, recovery and social support engagement, past month substance use, and psychosocial well-being
Kleinman et al (2021)	Implementation evaluation using RE-AIM framework (n = 199 contacts)	Community resource center for people experiencing homelessness or low income	N/A	Costs: Participant characteristics with potential cost implications Effects: Uptake of PRSS. Linkage to treatment services and re-linkage if left treatment Costs: Service utilization for PRSS, linkage to treatment and post-treatment linkage contacts
Liebling et al (2021)	Non-experimental, descriptive.	Hospital	N/A	Costs: Numbers of patients and potentially cost-related characteristics of patients. Service utilization for PRSS within a hospital
London et al (2018)	Cross-sectional, descriptive	PRSS in opioid use disorder care across a variety of settings	N/A	Costs: Funding sources for PRSS in variety of opioid use disorder care settings. Staffing characteristics for 7 programs including number of staff, hours, caseloads, fringe/benefits, and supplies.
Long et al (2020)	Non-experimental, descriptive	Single hospital observation unit	N/A	Effects: Buprenorphine (27.9%) and methadone (46.4%) treatment and 10% discharge against medical advice among those engaged in PRSS in hospital
Magidson et al (2021)	Quasi-experimental, single-group, 2 time points (n = 1171)	General medical settings in single health system	N/A	Effects: Initiation of and engagement in buprenorphine treatment. Opioid abstinence. Costs: PRSS utilization. General medical service utilization including ED and outpatient care.
Mangrum et al (2018)	Quasi-experimental, single group, 4 time points (participants n = 26IO, peer workers n = 2l5)	Recovery community organizations, community-based organizations and treatment organizations in Texas	Peer worker demographics. Recovery experience of peer workers. Length of work experience, training and credentialing for peer workers. Types of services delivered. Tenure at site and site turnover	Effects: Housing, employment, abstinence or reduced substance use and recovery capital all improved at 12-month follow-up compared to baseline. Re-engagement with recovery after returning to use Costs: Averted medical costs. Paid versus volunteer PRSS provision. Turnover at sites by site type
Mills Huffnagle et al (2022)	Quasi-experimental, 2 group (PRSS n = 47, no PRSS n = 230)	Single opioid treatment program site	N/A	Effects: PRSS associated with higher likelihood of attending more medical appointments Costs: PRSS service utilization
Mills Huffnagle and Kawasaki (2020)	Non-experimental, observational (n = 66)	Same as Mills Huffnagle et al, 2022	N/A	Effects: Significant positive correlation between the number of PRSS appointments and numbers of medical appointments and individual therapy appointments
Min et al (2007)	Quasi-experimental, two-group (PRSS n = 106, control = 378)	Dual-diagnosis long-term PRSS	N/A	Costs: Service utilization. Averted re hospitalizations
O’Connell et al (2017)	Randomized controlled trial with 3 arms (PRSS + skills training n = 42, skills training n = 48, treatment as usual = 47)	Outpatient dual-diagnosis treatment	N/A	Effects: Significant improvements in mental health and substance use among PRSS group Costs: Averted re hospitalizations among the PRSS group and longer retention in outpatient care
Open Minds (2018)	Cross-sectional, search of publicly available data	Multiple	N/A	Costs: Medicaid reimbursement rate information for 7 US states
Page et al (2017)	Cross-sectional, search of publicly available data	Multiple, all US states	Information about credentialing requirements, reimbursement and scopes of practice for behavioral health workers including peer workers. Greater detail on peer workers is provided in Videka et al (2019)	N/A
Ray et al (2021)	Randomized controlled trial (PRSS n = 46, control n = 54)	Post-incarceration re-entry	N/A	Effects: Significant improvement in perceived choice and self-efficacy, but null effects on treatment motivation, stage of change, general quality of life, and substance use. Reported retention in PRSS condition through I2months
Samuels et al (2015)	Quasi-experimental, single group, 2 time points (n = 856 charts)	Hospital	N/A	Effects: Linkage to treatment from hospital by peer workers. Remaining results unable to disambiguate what is attributable to PRSS
Scannell (2021)	Multi-site qualitative study (n = 10 peer workers)	Multiple sites in Massachusetts	Positive and negative experiences of the peer worker role. Recommendation for supervision by fellow peers, and expression of importance of good supervision to overcome negative aspects of the work.	N/A
Schutt et al (2021)	Randomized controlled trial (PRSS n = 85, control n = 8l)	Supportive housing program for veterans with dual-diagnosis	N/A	Effects: PRSS significantly positively associated with use of preventive mental health and SUD services at Veterans Affairs. Significantly less housing instability among those with more drug use at baseline, but worse housing instability among those with more psychiatric problems at baseline
Stone king and McGuffin (2007)	Quasi-experimental, single group with 2 time points (n = 68 peer worker trainees)	Arizona peer worker training program	Significant improvement in all knowledge and attitudes/skills training concepts measured from pre- to post-training. A 3-month post-training assessment by supervisors was compared to self-assessments and 81% concordance between supervisor and self-assessment was found	N/A
Tate et al (2022)	Multi-site qualitative focus groups (n = 63 peer workers) and cross-sectional survey (n = 35 trainees, n = 25 certified peer workers)	Multiple sites in 1 Northeastern state	Funding problems contributing to negative work experiences but also describes positive aspects of the work. Full cross-sectional survey results not presented, but highlights included in the text are prevalence of training funding and support for training, manageability of caseload, and concerns about taking time from work to care for own mental health	N/A
Videka et al (2019)	Cross-sectional, search of publicly available data	Entire United States	Availability of peer services and density of peer services for entire United States as well as by state and by characteristics of sites where peer services are provided. Funding mechanisms and presence/absence of peer services, stratified by service provider type and other characteristics
Waye et al (2019)	Non-experimental, descriptive.	Emergency department and community-based outreach	N/A	Effects: Referrals by PRSS and peer worker engagement Costs: Distribution of naloxone kits and naloxone trainings

Abbreviations: PRSS, peer recovery support services; ED, emergency department; SUD, substance use disorder; N/A, not applicable.

Manuscripts with Workforce-Related Outcomes

Of the 22 papers with workforce-related outcomes, 4 included quantitative details about peer workers and PRSS working conditions,^16–20 5 had quantitative information about peer worker trainees,^20–24 and 10 were qualitative studies with themes relevant to the peer workforce.^3,20,25–32 An additional 4 manuscripts were relevant but were descriptive,^18,33 pertained to infrastructure,¹⁴ or represented expert guidance.³⁴

Peer Workers and Characteristics of Performing PRSS.

Quantitative studies of peer workers or characteristics of performing PRSS included findings related to peer worker pay, credentialing, specific services and settings, peer worker demographics, and attitudes toward different aspects of the work. Medicaid reimbursement rates for SUD peer workers ranged from $5.75 to $24.49 per 15-minute increment (mean $12.98) across 31 states using the following billing codes: H0038, H0046, H2015, H2017, H2019, or T1012.¹⁷ Median annual salary for peer workers and their supervisor at a single Federally Qualified Health Center (FQHC) was $34 000 and $45 000, respectively, excluding benefits.¹⁸ Hagaman¹⁹ reported categorical pay information from 562 peer workers Appalachian peer workers, and found that 1.2% were paid less than $10, 47% were paid $10 to $15, 33% were paid $16 to $20, and 19% were paid more than $20 per hour. Mangrum et al¹⁶ found that 72% of 215 organizations providing PRSS across Texas had paid peer workers only, 20% had both paid and volunteer peer workers, and 9% were volunteer-only. Tate et al²⁰ found that 76% of 25 peer workers within 1 Northeastern state were paid for their services and 8% were unpaid.

Beck et al¹⁷ found 63 types of peer worker credentials across 49 US states. All required a minimum high school diploma or General Educational Development (GED) and required classroom training (median = 46 hours, range 6–126), whereas only 34 credentials required experiential hours (median = 500, range 72–2000).¹⁶ Only 39 of the 63 credentials required an attestation of being in recovery, and 18 credentials had a specific minimum recovery time required (mean = 18 months, range 6–24 months).¹⁷

Services covered under peer worker credentials included recovery assistance, mentorship, advocacy, health education, system navigation, and social/emotional support, and no credentials authorized peer workers to provide services independently.¹⁷ Hagaman¹⁹ reported that sharing recovery stories was the most frequent activity (96%) and was the skill most peer workers rated moderate to very strong (91%), whereas financial education was both the least frequent activity (66%) and the least-frequently cited as a moderate to very strong skill (47%).¹⁹ Appalachian peer workers also reported time spent engaged in PRSS strategies from the Recovery-Ready Ecosystem Model,³⁵ the 4 SAMHSA-defined peer support types,³⁶ and primary work setting.¹⁹ The most common primary work setting was “other” (29%), and the least-endorsed settings were collegiate recovery program (1%) and child welfare agency (0.2%).¹⁹ Within Texas, SUD services (97%), family support (51%), and co-occurring SUD and mental health services (50%) were provided most frequently, whereas the least-common categories were veteran’s services (19%) and other (11%).¹⁶

Only Hagaman¹⁹ and Mangrum et al¹⁶ reported on peer worker demographics: both found that peer workers were majority female (67% and 57%, respectively) and White (68% and 58%, respectively), and had similar age profiles (mean age = 46.37 and 44% in the 46–55 age category, respectively). Hagaman¹⁹ also reported years in recovery (mean = 10.44, SD = 8.46), medications peer workers used to support their recovery, criminal legal system involvement, current financial fragility (33% financially fragile), and number of years in the SUD field (mean = 5.99, SD = 5.87). Among Appalachian peer workers, current mean site tenure was 3.6 years (SD = 3.78),¹⁹ whereas Mangrum et al¹⁶ estimated turnover in Texas at 62% across all organizations providing PRSS (65% at treatment organizations and 55% at recovery community organizations).

Hagaman reported a mean job satisfaction score of 31.51 (SD = 6.51, max. 40) indicating that peer workers were generally satisfied with their work,¹⁹ and there was a significant positive association between hourly wage and job satisfaction score. The smaller Tate et al²⁰ study found that caseloads were generally considered manageable by peer workers (72%, with 8% unmanageable caseloads), that most peer workers felt they had adequate time with participants (72% yes, 16% no), and that peer workers felt well-matched to participants (84% yes, 8% no). More than half of Tate et al²⁰ peer workers worried about their job security if they took time to care for their own mental health (52%). Only 42% of Appalachian peer workers¹⁹ said that opportunities for career advancement were very often or always available, whereas 8% of them said these opportunities were never available. Finally, Hagaman¹⁹ found that 66% of peer workers were supportive of participants using medications for opioid use disorder, whereas 16% of them were not supportive.

Training Peer Workers.

The 5 training-related manuscripts included trainee demographics, training outcomes, and support during training.^20–24 Among peer worker trainees, both Castedo de Martell et al²¹ and Hansen et al²³ found that most were women or female (58.6% and 51.6%, respectively), and there was good representation among minority racial and ethnic groups. Among 448 peer worker trainees, 66% held a high school diploma or GED as the highest level of education, and 53% had a history of criminal legal system involvement.²¹ A third (34%) of trainees achieved full certification, and past support from a peer worker, having a history of criminal legal system involvement, and having a bachelor’s degree were all significantly positively associated with achieving full certification.²¹

Two studies^22,24 found significant improvement in training areas from pre- to post-training, and Stoneking and McGuffin²⁴ found that supervisors’ ratings of trainees’ skills were either identical or higher than the trainees’ self-assessment. Hansen et al²³ found only a slight decrease in perceptions training benefits (5%), with the exception of perceived benefit to participants, which declined from 96.1% to 80.9% (a 15.2% decrease) at 6-month post-training follow-up. Finally, Tate et al²⁰ found that one-third of participants had their training funded, and that trainees were overwhelmingly supported by family and significant others (91.4%).²⁰

Qualitative Themes.

Ten qualitative papers had themes that were directly relevant to the peer workforce.^3,20,25–32 Hamso et al³⁰ and Hymes³¹ described the positive impacts of performing PRSS on the peer worker’s own identity, relationship to their own recovery (including their own use of medications for opioid use disorder), career outlook, financial stability, social approval, and motivations to be a peer worker.

Anvari et al²⁶ described the changes in PRSS provision due to the COVID-19 pandemic, and these changes were not universally disruptive to the peer workers’ performance of their duties: some changes, like more online recovery support meetings, are positive. Similarly, Collins-Pisano et al²⁹ interviewed peer workers, supervisors, and other PRSS experts on digital PRSS provision core competencies in light of the COVID-19 pandemic.

Two qualitative studies^3,25 described experiences of stigma among peer workers while performing PRSS, but Scannell³² also found peer workers felt they could help reduce stigma in their environment. These experiences of stigma may be related to challenges with integration into multidisciplinary treatment teams,^3,25,32 but positive experiences were also shared.²⁷ Peer workers shared challenges navigating boundaries^20,25 and lack of role clarity.³² Two studies^25,27 described challenges with and recommendations for hiring peer workers. Some peer workers expressed a desire for additional training to manage burnout but highlighted that underfunding of the organization contributed directly to feeling overburdened.²⁰ Others pointed to specific settings as being stressful: the hospital environment²⁸ or settings where participants face substantial systemic barriers.³² Importantly, these feelings of stress and being overburdened intersected directly with being underpaid and having meager benefits packages in 3 studies.^3,20,25

Infrastructural, Guidance, and Example Items.

Two example items were included: an example of a peer worker’s role within a hub and spoke system³³ and a detailed protocol for the delivery of long-term PRSS.¹⁸ One report provided an overview of PRSS infrastructure by US state, stratified by facility and service type, across both SUD and mental health peer services.¹⁴ The density of PRSS across the United States was reported at 2.08 per 100 000 for SUD treatment facilities offering PRSS.¹⁴ Finally, 1 report gave general guidance for typical service utilization, caseload recommendations, recommendations on qualification requirements, and service roles.³⁴

Potential Economic Evaluation Parameters

Of the 26 manuscripts that included potential economic evaluation parameters, there were 19 with potential cost parameters^{14,16–19,34,37–49} and 17 with potential effect parameters.^{16,18,37–42,45,49–56}

Costs.

Potential cost parameters fall into 2 major categories: service provision costs and averted costs. Averted costs include societal (eg, avoided arrests) and health system (eg, reductions in emergency department [ED] visits).^11,12

Manuscripts containing information about peer worker pay were described in section “Peer workers and characteristics of performing PRSS.” However, one additional report⁴⁸ presents the same information as Beck et al¹⁷ but only for select states. In 1 study of peer workers providing SUD screening in the ED, peers worked 20 hours/week,⁴¹ and for 7 programs providing PRSS and support for people with opioid use disorders, weekly hours worked ranged from 37.5 to 40 for full-time and 10 to 29 hours for part-time peer workers.⁴⁴ Caseloads ranged from a maximum of 35 to 50 participants per peer worker to a minimum of 8 to 12 per peer worker,⁴⁴ whereas agency-wide caseloads ranged from 4500 participants to a minimum of 175 to 200.⁴⁴ Per-year cost of supplies for each peer worker was approximately $1500 to $5000 per coach, and fringe costs ranged from 18% to 35% of annual salary per peer worker.⁴⁴ Two studies provided limited information about funding sources for organizations providing PRSS.^14,44

Hospital-based PRSS service utilization was described across 4 studies. Patients who were hospitalized with SUD complications were engaged by peer workers after discharge 7 to 15 times per patient per month (mean = 9.7, SD = 3.0).³⁹ Approximately 148 patients were screened for every 1 patient successfully linked to ED-initiated buprenorphine in a peer worker-led universal screening/referral program.⁴¹ Liebling et al⁴³ reported referral rates for hospitalized patients referred to peer workers within the hospital, demonstrating substantial growth but also substantial repeat visits (62.2% unique patients). The duration of hospital-based peer worker visits were 35 minutes on average at the main study site (50 minutes at other sites).⁴³ Among patients who experienced an overdose, 12.8% refused peer worker consult (9.5% refusal among those without overdose) and 51.5% accepted a peer worker (48% among those without an overdose).⁴³ In a general medical setting, 1171 patients were engaged during the study period and spent a median of 120 minutes and 4 contacts with a peer worker over a median of 51 days.⁴⁵

At a FQHC, participants engaged in an average of 6.02 visits with a peer worker over 6 months (SD = 7.98).¹⁸ At a community resource center, 39 of 199 engaged participants agreed to discuss SUD, 28 completed a full intake with a peer worker and had an average of 3.8 (SD = 2) contact attempts from the peer worker after linkage to treatment.⁴² In a drug court, participants had an average 11.5 contacts (phone or in person, range 1–25) with their peer worker.³⁸ At an outpatient buprenorphine facility, participants attended 14 appointments on average with peer workers (SD = 18.2) over an average of 6.5 months (SD = 7.2 months).⁴⁶ Across 20 recovery community centers, 3459 participants engaged in an average of 130.68 days (SD = 171.73) of PRSS, with each engagement lasting 27.95 minutes on average (SD = 17.11).³⁷ Total service use for the 3459 participants was 4290 recovery planning and follow-up engagement sessions, 8913 brief check-ins, 352 referrals, 1560 recovery plan goal creation sessions, 9520 mutual aid meetings, 2125 pro-social events, 800 education activities, and 540 advocacy activities.³⁷ Finally, Faces & Voices of Recovery³⁴ provided guidance on service utilization patterns across different lengths of recovery time, as well as recommendations on periodicity of service needs reviews.

Gertner et al⁴¹ reported that 42% of hospitalized patients who screened positive for substance use problems were uninsured, and Liebling et al⁴³ found that 11.4% of hospitalized patients who had experienced an opioid overdose had private insurance. Participants in an American Indian PRSS program had a monthly average income of $690 at intake (SD = $2984). PRSS participants in Texas had an average monthly income of $258 at intake and $881 at 12-month follow-up.¹⁶

The only specific estimate of averted medical costs was found in Mangrum et al: an estimated $3.5 million in healthcare costs were saved due to a 74% reduction in high-cost emergency healthcare use among PRSS participants at 12 months across outpatient, inpatient, and ED settings.¹⁶ Magidson et al⁴⁵ found a significant decrease in percent of patients with hospitalizations (40.7% at baseline to 22.6% at 6 months post-PRSS, rate ratio = 0.56, P < .001) and in total number of hospitalizations (869 at baseline, 468 at 6 months post-PRSS, rate ratio = 0.54, P < .001). However, only the percentage of patients with any ED visits decreased significantly, but not the number of ED visits.⁴⁵ Among dually diagnosed participants, there was a significant reduction in hospitalizations among those using PRSS across 2 studies.^47,53 For people who engaged with a peer worker during an ED visit, only 8.2% experienced a re-admission to the ED.⁴⁰ For those engaged in long-term PRSS at a recovery community center, there was an average of 0.02 ED visits per person (SD = 0.26).³⁷ Finally, in a post-overdose ED engagement of PRSS, 89% of those who received PRSS (n = 1392) in the ED also received a naloxone training, and 854 total naloxone kits were distributed.⁴⁹

Effects.

Outcomes measured in PRSS studies that may be useful in future economic evaluation research include substance use outcomes, quality of life and life functioning outcomes, and engagement in or linkage to care. Ashford et al³⁷ reported 323 recurrences of substance use among 3459 participants, which was an average of 0.9 recurrence of use events per individual (SD = 0.61). Participants in an American Indian long-term PRSS program had significantly fewer substance use days at 6-month follow-up (mean = 0.1 days) compared to baseline (mean = 0.19 days in the past 30 days).⁵⁰ At a 12-month follow-up, 83% of participants in long-term PRSS in Texas were abstinent or had sustained substance use reductions, and, of the 40% of participants with a recurrence of use at 2-year follow-up, 77% reached out to their peer worker for help and 62% were in recovery again within 1 month.¹⁶ Magidson et al⁴⁵ found a significant association between current month contact with a peer worker and opioid abstinence (OR = 1.32; 95% CI: 1.02–1.70). In another general medical setting, participants in PRSS had a significant reduction in past-month substance use at 6-month follow-up (χ² = 57.57, df = 1, P < .001)¹⁸ Among dually diagnosed participants, there was a significant decrease in drinking days among those engaged in PRSS (t(61) = 3.15, P = .002, b = 8.14), and fewer days experiencing alcohol problems (t(36) = 4.40, P = .001, b = 6.87).⁵³ However, 2 randomized controlled trials found null effects of PRSS on substance use outcomes for those engaged in drug courts³⁸ and among hospitalized patients linked to PRSS.³⁹

No studies measured quality of life changes using a measure that can be converted to utility, which is used to estimate quality-adjusted life years (QALYs) in economic evaluations. However, 1 study used the PHQ-9,¹⁸ which has been mapped to the EQ-5D, a QALY-compatible measure, for a different health condition and intervention.⁵⁷ Participants in PRSS had significantly reduced PHQ-9 scores at follow-up (mean = 7.80, SD = 5.79) compared to baseline (mean = 10.42, SD = 5.83; t = 4.94, df = 142, P < .001).¹⁸

One study³⁸ detected a lower percentage of arrests compared to the non-PRSS group, but another study¹⁸ reported a small but significant increase in days in jail or prison and arrests. Increases in recovery capital were reported in 2 single-group quasi-experimental studies between baseline and follow-up.^16,37 Significant increases in housing stability were found in 3 studies,^16,50,56 and 3 studies found significant improvements in employment and income among PRSS participants.^18,50,58 Kelley et al⁵⁰ reported improvements in school or training enrollment, social interactions, health status, and the impact of substance use on functioning. Significant positive change was found across psychosocial measures in 2 additional studies^53,54 but Byrne et al³⁹ found null effects.

Five studies^{40,41,49,51,55} reported rates of linkage to SUD treatment services including medications for opioid use disorder among hospitalized patients engaging with peer workers, and 2 studies^18,45 reported similar rates but in general medical settings. Treatment engagement and linkage to treatment was also reported for a community resource center,⁴² among drug court participants,⁵⁴ and in long-term PRSS with American Indians.⁵⁰ Finally, Mills Huffnagle and Kawasaki⁵² found that higher PRSS appointments were associated with greater engagement in medical and individual therapy appointments and longer treatment retention.

Discussion

One of the most pressing remaining gaps in the literature related to the peer workforce is to explore potential associations between peer worker job satisfaction and site tenure, and to test whether site tenure or other measures of peer worker experience are associated with patient outcomes or quality of care. The association between job satisfaction and peer worker pay has been explored at the regional level¹⁹ and should be explored at the national level and expanded to other organizational characteristics such as those developed for mental health peer services organizational culture.⁵⁹ A second gap is the ability to follow up with former peer workers who leave an organization or PRSS altogether, in order to determine whether attrition is due to working conditions or due to individual resilience factors. Disambiguating training needs that reflect the moving targets of a constantly evolving landscape of substance use from persistent training needs is also key. For example, new substances or contaminants will continually enter the national supply, and the prevalence of certain kinds of substance use will wax and wane while overall SUD prevalence remains roughly stable. However, calls for better training about trauma-informed care and managing burnout are likely to be important topics for decades to come, and should be incorporated into standard trainings for peer workers.

Future studies of PRSS should continue to report service utilization patterns, and, where practical, report other costs associated with service provision, including peer worker pay, benefits, and other expenses. This is especially key as PRSS expands into novel settings and employs varied strategies. Changes in behaviors that can be translated into averted societal or medical costs are also of great use to future economic evaluations and should continue to be recorded across settings, populations, and types of PRSS engagement.

Currently, only 1 study presents quality of life changes using a measure for which a QALY-compatibility conversion method exists.^35,57 Studies of sustained engagement in buprenorphine treatment have operationalized treatment success as abstinence from other types of opioids, or maintenance on buprenorphine, and estimated maintenance utility.⁶⁰ This approach is fitting for economic evaluations of medications for opioid use disorder, but may not be appropriate for economic evaluations of PRSS and other interventions centering general SUD recovery as the primary outcome. Recovery utility for QALY estimation is currently not established in the literature, and future research is needed. However, existing studies demonstrate that it is feasible to collect other key information that informs economic evaluation studies as part of PRSS research: other medical service utilization, service delivery patterns, and peer worker compensation are all present in various forms across the literature, ready to inform future economic evaluations of PRSS.

Conclusions

This review provides researchers wishing to address 2 major gaps in PRSS literature with a clear delineation of the literature surrounding those gaps, as well as highlighting priority remaining gaps. As PRSS continues to expand across the United States, the need to better support this workforce and adequately fund these services is especially salient.

Highlights.

• Gaps remain in the peer recovery support services (PRSS) literature and highlighting these gaps can help spur research.

• The peer workforce is under-studied, and research on retaining peer workers is needed.

• PRSS economic evaluation parameters are available in the literature, but estimating utility and some cost categories is currently challenging.