Reappraisal of the Population-Based Incidence of Colonic Ischemia

Introduction: Colonic Ischemia (CI) is the most common cause of gastrointestinal ischemia, accounting for 50-60% of cases. Recent epidemiological studies have shown approximately a quadruple increase in incidence of CI from 1970 to 2009. The aim of this study was to reassess changes of CI in Olmsted County (OC), Minnesota. Methods: The Rochester Epidemiology Project (REP) was used to identify residents of Olmsted County diagnosed with CI between 1/1/2010 to 12/31/2019. ICD-9, ICD-10 and HICDA diagnosis codes were used to identify CI patients, and they were further filtered with radiology (Computed Tomography Scan/Magnetic Resonance Imaging), colonoscopy with biopsy, intraoperative note or autopsy reports using retrospective chart review. Definite diagnosis was defined as patients with biopsy proven colonic ischemia. Patients with inflammatory bowel disease, colon cancer, bowel obstruction, volvulus leading to bowel ischemia were excluded. Incidence rates were age- and sex-adjusted to the 2010 U.S. White Census and modelled using Poisson regression. Results: A total of 313 patients with a definitive or probable diagnosis with colonic ischemia were identified. Median age of diagnosis was 69.9 years (IQR 59.7-79.4) and 70.3% were females. Other baseline characteristics and descriptive outcomes are mentioned in Table 1. The overall age- and sex-adjusted total incidence was 22.4 (95% CI 19.9-24.9, per 100,000 person-years. The age-adjusted incidence in females was significantly more than males (28.8 vs 14.9 per 100,000 person-years, IRR 1.9, 95% CI 1.5-2.5, P < 0.001). Figure 1b shows the increasing sex-adjusted age incidence rates with a steep increase after age 40-59 years [IRR vs age 0-39 11.5, 95% CI 6.4-20.8, P < 0.001] up to 80+ years (IRR vs age 0-39 80.7, 95% CI 44.8-145.5, P < 0.001. Overall, the incidence of colonic ischemia shows a downward trend by year (IRR 0.94, 95% CI 0.90-0.98 P = 0.001) (Figure 1a). Conclusion: Although the overall incidence of CI is showing a downward trend in OC over the most recent decade, there is an increased incidence for females and larger ages. Table 1. - Baseline Characteristics of Incident Cases of Colonic Ischemia Between 2010-2019 in Olmsted County Baseline Characteristics N (%) Gender, Female 220 (70.3%) Age of Diagnosis, Median (IQR) 69.9 (59.7-79.4) BMI, Median (IQR) 23.1 (20.1-27.0) Charlson Severity-Weight Score, Mean (SD) 1.7 (2.3) Patients Requiring Hospitalization 217 (69.3%) Mean Duration of Hospital Stay (SD) 8.5 (18.8) Patients Requiring Colectomy 30 (9.6%) Figure 1.: (a) Age and Sex-Adjusted Incidence Rates Per 100,000 Person-Years from 2010 to 2019; (b): Sex Adjusted Age Incidence Rates Per 100,000 Person-Years.