Rural-Urban and Appalachian Disparities in Geographic Access to Colonoscopy and Screening Prevalence Across the Contiguous US.

Abstract

Introduction: Colorectal cancer (CRC) incidence and mortality rates are disproportionately high in rural and Appalachian communities, where geographic barriers and specialist shortages may limit access to colonoscopy.

Methods: We conducted a national cross-sectional geospatial analysis of all contiguous US census tracts. We identified colonoscopy providers by using National Provider Identifier specialty designations and colonoscopy procedure indicators. Geographic access was quantified by using a 4-band enhanced 2-step floating catchment area (E2SFCA) method. We used small-area estimation for colonoscopy from Centers for Disease Control and Prevention PLACES to determine CRC screening prevalence. We compared E2SFCA distributions across rural-urban and Appalachian-non-Appalachian using the Kruskal-Wallis test with Benjamini-Hochberg-adjusted Dunn post hoc pairwise comparisons; we modeled screening prevalence using a mixed-effects beta regression analysis.

Results: Urban census tracts tended to rely on delivery of colonoscopies by gastroenterologists and ambulatory surgical centers, whereas rural census tracts relied more on general surgeons, particularly for screening (vs diagnostic/therapeutic colonoscopy). Geographic access to colonoscopy providers varied little across census tracts, with only modest differences by rurality and Appalachian designation. In mixed-effects beta regression, colonoscopy access was not significantly associated with screening prevalence while both rural and Appalachian census tracts had slightly lower screening prevalence compared with their counterparts (rural vs urban: Exp(β) = 0.994; P = .02; Appalachian vs non-Appalachian: Exp(β) = 0.976; P < .001).

Conclusion: Better geographic access does not translate into meaningfully higher screening prevalence. Structural, socioeconomic, and referral-related barriers likely attenuate the effect of geographic proximity on screening behavior. Further integration of claims-based utilization and patient-level factors is needed to clarify pathways between access and CRC screening.