{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T16:37:24Z","timestamp":1787330244840,"version":"build-2736575974"},"reference-count":87,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T00:00:00Z","timestamp":1787270400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000009","name":"NIH","doi-asserted-by":"publisher","award":["R03 AG085084-01"],"award-info":[{"award-number":["R03 AG085084-01"]}],"id":[{"id":"10.13039\/100000009","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000009","name":"NIH","doi-asserted-by":"publisher","award":["R01 AT009491-01A1"],"award-info":[{"award-number":["R01 AT009491-01A1"]}],"id":[{"id":"10.13039\/100000009","id-type":"DOI","asserted-by":"publisher"}]},{"award":["R03 AG085084-01"],"award-info":[{"award-number":["R03 AG085084-01"]}],"id":[{"id":"https:\/\/ror.org\/00k86s890","id-type":"ROR","asserted-by":"publisher"}]},{"award":["R01 AT009491-01A1"],"award-info":[{"award-number":["R01 AT009491-01A1"]}],"id":[{"id":"https:\/\/ror.org\/00k86s890","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Environ. Res. Public Health","IJERPH"],"abstract":"<jats:p>Limited inclusion of ethnically diverse and socioeconomically disadvantaged populations in pain research undermines external validity, generalizability, and equity. This comprehensive review synthesized evidence on effective strategies to recruit and retain these populations in pain studies. We searched Medline, Web of Science, Embase, Scopus, and CENTRAL (12 April 2025) and included studies in which ethnically diverse and socioeconomically disadvantaged participants comprised \u226575% of the sample. Quantitative data were pooled using random-effects meta-analyses of proportions, with prespecified subgroup analyses, and qualitative findings were integrated through thematic synthesis. Certainty of evidence was evaluated using GRADE. Eighteen studies (n = 4611; 11 experimental, 5 observational, 2 qualitative), primarily from the United States and involving chronic pain, met inclusion criteria. Overall enrollment among ethnically diverse and socioeconomically disadvantaged groups was 37% (95% CI 18\u201358%), with significantly higher enrollment in observational studies (84%, 95% CI 78\u201390%) than in experimental trials (22%, 95% CI 10\u201336%; p &lt; 0.001). Overall retention was 77% (95% CI 64\u201388%) and did not differ significantly by study design. Statewide disease-clinic networks, purposive community-leader engagement, and snowball sampling produced the highest enrollment, whereas medical-record screening yielded the lowest enrollment but the highest retention. Compensation and reminder strategies were similarly effective for retention. Thematic synthesis highlighted trust, culturally and linguistically tailored communication, hybrid and flexible visit schedules, transportation assistance, and clinician engagement as key facilitators. GRADE certainty was low for enrollment and moderate for retention. Community-engaged recruitment strategies, clinician referrals, culturally tailored materials, hybrid procedures, and modest incentives can substantially improve participation of ethnically diverse and socioeconomically disadvantaged populations in pain research. Standardized CONSORT-style reporting of recruitment\/retention flowcharts according to strategy and ethnicity\/socioeconomic status is essential to refine evidence-based strategies in the future.<\/jats:p>","DOI":"10.3390\/ijerph23081091","type":"journal-article","created":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T15:51:05Z","timestamp":1787327465000},"page":"1091","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Improving Inclusion of Ethnically Diverse and Socioeconomically Disadvantaged Populations in Pain Research: A Comprehensive Review and Evidence-Based Recommendations"],"prefix":"10.3390","volume":"23","author":[{"given":"Kevin","family":"Pacheco-Barrios","sequence":"first","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"},{"name":"Unidad de Investigaci\u00f3n para la Generaci\u00f3n y S\u00edntesis de Evidencias en Salud, Vicerrectorado de Investigaci\u00f3n, Universidad San Ignacio de Loyola, Lima 15023, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Allison","family":"Kim","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"},{"name":"Admission AG, Irvine, CA 92618, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-3624-5185","authenticated-orcid":false,"given":"Carla","family":"Pastora-Sesin","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-7309-918X","authenticated-orcid":false,"given":"Joao","family":"Mariano","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-3208-5547","authenticated-orcid":false,"given":"Robin","family":"Heemels","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2387-8970","authenticated-orcid":false,"given":"Paulo S.","family":"de Melo","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0678-9351","authenticated-orcid":false,"given":"Erick","family":"Barrientos-Ventura","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n para la Generaci\u00f3n y S\u00edntesis de Evidencias en Salud, Vicerrectorado de Investigaci\u00f3n, Universidad San Ignacio de Loyola, Lima 15023, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucas","family":"Camargo","sequence":"additional","affiliation":[{"name":"Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Niels","family":"Pacheco-Barrios","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Mass General Brigham, Harvard Medical School, Boston, MA 02215, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4428-9489","authenticated-orcid":false,"given":"Jaime","family":"Pacheco-Neyra","sequence":"additional","affiliation":[{"name":"Research Unit, Our Lady of Chapi Pharmacy, Cajamarca 06001, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Silvia","family":"Di-Bonaventura","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Rey Juan Carlos University, 28922 Alcorcon, Spain"},{"name":"Research Unit, Bei App, 28023 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5495-8458","authenticated-orcid":false,"given":"Ra\u00fal","family":"Ferrer-Pe\u00f1a","sequence":"additional","affiliation":[{"name":"Clinical and Teaching Research Group on Rehabilitation Sciences (INDOCLIN), CSEU La Salle, Universidad Aut\u00f3noma de Madrid, 28023 Madrid, Spain"},{"name":"Centro de Salud Entrev\u00edas, Gerencia Asistencial de Atenci\u00f3n Primaria de la Comunidad de Madrid, 28023 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alba","family":"Navarro-Flores","sequence":"additional","affiliation":[{"name":"Institute of Psychiatric Phenomics and Genomics (IPPG), LMU University Hospital, LMU Medizin, Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen, 80336 Munich, Germany"},{"name":"International Max Planck Research School for Translational Psychiatry (IMPRS-TP), 80804 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"name":"Equity in Pain ResearchWorking Group (EPR-WG)","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1976","DOI":"10.1097\/j.pain.0000000000001939","article-title":"The revised IASP definition of pain: Concepts, challenges, and compromises","volume":"161","author":"Raja","year":"2020","journal-title":"Pain"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1003","DOI":"10.1097\/j.pain.0000000000000160","article-title":"A classification of chronic pain for ICD-11","volume":"156","author":"Treede","year":"2015","journal-title":"Pain"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1097\/01.ajp.0000148627.92498.54","article-title":"Fear-avoidance beliefs as measured by the fear-avoidance beliefs questionnaire: 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