Gastroenterology · Medical Literature
Recruiting Rural Patients for Clinical Research: Lessons From a Colorectal Cancer Screening Trial.
Abstract
The Colonoscopy Outreach for Rural Communities (CORC) study is a randomized controlled trial testing the effectiveness of a remotely-delivered patient navigation program to increase colonoscopy completion for colorectal cancer (CRC) screening among rural and underserved patients. This study assesses CORC's success in recruiting rural patients and outlines approaches for including rural residents in clinical research. We conducted descriptive analyses of rurality designations for enrolled patients based on their ZIP code using the Federal Office of Rural Health Policy (FORHP) definition and Rural-Urban Commuting Area (RUCA) codes. The primary care organization (PCO) partnership was based on Rural-Urban Continuum Codes (RUCCs). To recruit patients, CORC partnered with two PCOs in urban counties (RUCC = 3) and four PCOs in rural counties (RUCC >3). Of 527 participants, 75% (n = 394) lived in rural areas overall; 43.3% resided in large rural areas, 38.3% in small rural areas, and 18.4% in isolated rural areas. Nearly all (97.3%) participants recruited from the four PCOs located in rural counties lived in FORHP-designated rural areas, whereas urban PCOs contributed both rural (53.3%) and urban participants. Partnering with rural PCOs in a pragmatic clinical trial led to successful recruitment of rural patients. Working with PCOs in urban counties also contributed to successful rural patient recruitment. Several key approaches included partnering with primary care to reach patients in their communities, using multiple strategies to understand PCO's populations served, and tailoring recruitment to rural patients' unique needs. These strategies may help researchers increase the representation of rural populations in clinical research.
Clinical relevance
Rural populations face disproportionate barriers to colorectal cancer (CRC) screening and are chronically underrepresented in clinical research, limiting the generalizability of trial findings to this high-risk group. The CORC trial directly addresses this gap by evaluating a remotely-delivered patient navigation intervention to increase colonoscopy completion among rural and underserved patients. Given persistent rural-urban disparities in CRC incidence and mortality, identifying effective recruitment strategies for rural patients is an urgent priority for both trialists and practicing gastroenterologists.
Key findings
1. Of 527 total participants enrolled in the CORC randomized controlled trial, 75% (n = 394) resided in FORHP-designated rural areas, demonstrating a high rural recruitment yield. 2. Among rural participants, 43.3% lived in large rural areas, 38.3% in small rural areas, and 18.4% in isolated rural areas — reflecting meaningful heterogeneity within the rural stratum. 3. Partnership with four primary care organizations (PCOs) located in rural counties (RUCC >3) yielded near-complete rural recruitment: 97.3% of participants from those sites were FORHP-designated rural residents. 4. Two PCOs in urban counties (RUCC = 3) contributed a mixed population: 53.3% of their recruits were rural residents, demonstrating that urban-situated PCOs serving rural catchment areas can supplement rural enrollment. 5. The trial employed multiple rurality classification systems simultaneously (FORHP definitions, RUCA codes, and RUCCs), highlighting the importance of using parallel frameworks to accurately characterize participant rurality. 6. Note: No inferential statistics, effect sizes, confidence intervals, or p-values were reported in the abstract for recruitment outcomes, as this report focuses on descriptive recruitment methodology rather than intervention efficacy.
Practice implications
Gastroenterology and primary care researchers designing CRC screening trials should prioritize direct partnerships with PCOs physically located in rural counties (RUCC >3), as this strategy achieved a ~97% rural recruitment rate in CORC and is more efficient than relying solely on urban referral networks. Trial protocols should incorporate tailored recruitment approaches that account for the heterogeneity within rural populations — distinguishing large rural, small rural, and isolated rural patients — since access barriers, health literacy, and navigation needs may differ substantially across these subgroups. Adoption of multiple rurality classification systems (FORHP, RUCA, RUCC) at the study design stage is recommended to enable more granular subgroup analyses and improve cross-trial comparability of rural health research findings.