P4161 - Diagnosis of GI Tract Cancers in New Onset Iron Deficiency Anemia in a National Retrospective Cohort (2005-2019)

Award: ACG Outstanding Research Award in the GI Bleeding Category

Award: Presidential Poster Award

Andrew J. Read, MD, MS¹, Hardeep Singh, MD, MPH², Sarah L. Krein, PhD, RN¹, Grace Y. Chen, MD, PhD¹, Amit G. Singal, MD, MS³, Jennifer Burns, MHS⁴, Kennedy Dubose, MPH⁴, Van Tony, MS⁴, Sameer D. Saini, MD, MS¹, Akbar Waljee, MD, MS^1
1University of Michigan, Ann Arbor, MI; ²Baylor College of Medicine / Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX; ³University of Texas Southwestern, Dallas, TX; ⁴Ann Arbor VA, Ann Arbor, MI

Introduction: Iron deficiency anemia (IDA) is considered an alarm sign, or “red flag,” as it may reflect occult GI bleeding from a gastrointestinal tract tumor. Bidirectional endoscopy with esophagogastroduodenoscopy (EGD) and colonoscopy is recommended for new-onset IDA. However, existing estimates of the risk of GI cancer in these patients are highly variable. Our study sought to determine the risk of luminal GI tract cancer diagnosis in the first 5 years after incident IDA in a national U.S. population.

Methods: We conducted a retrospective cohort study of individuals receiving regular care within the Veterans Health Administration (VA), as defined by at least 1 primary care visit every 2 years over a 5-year period. We identified individuals with normal baseline hemoglobin who subsequently developed anemia, as defined by WHO criteria (< 13 g/dL for men or < 12 g/dL for women), and who had a ferritin within 1 year of incident anemia (< 45 ng/ml as a cutoff for IDA per 2020 AGA guidelines). We used the national VA cancer registry to identify luminal GI tract cancer diagnoses within 5 years after incident anemia.

Results: Our cohort included 308,404 individuals (289,727 men, 18,677 women), of whom 94,765 (30.7%) had IDA. There were 3,079 (1%) individuals with luminal GI tract cancers diagnosed in 1 year, 4,286 (1.4%) within 3 years, and 5,028 (1.6%) within 5 years. In univariate analysis, we found the odds ratio (OR) of a luminal GI cancer diagnosis within 1 year was 4.4 (95% CI 4.1-4.7) in the setting of new-onset IDA compared to non-IDA. The risk of GI tract cancer in the setting of new IDA persisted but diminished over time: OR at 3 years was 3.6 (95% CI 3.4-3.8), and at 5 years was 3.1 (95% CI 2.9-3.3). When evaluating individual cancers in 1 year, IDA had the greatest risk for colon cancer (OR = 5.7, 95% CI 5.2-6.3), compared to gastric cancer (OR = 4.0, 95% CI 3.2-4.9), rectal cancer (OR = 2.5, 95% CI 2.0-3.1), and esophageal cancer (OR = 2.2, 95% CI 1.7-2.8).

Discussion: Evaluation of new-onset IDA is critical to identify potential GI tract cancers. Although the greatest risk was observed for colorectal cancer, upper GI cancers (esophageal and gastric cancer) were also increased, confirming the importance of bidirectional endoscopy in IDA. Given increased risk of GI cancer diagnosis up to 5 years after incident IDA, additional EHR tools and interventions are needed to improve evaluation of IDA and prevent diagnostic delays of GI tract cancers.


Disclosures:


Andrew J. Read, MD, MS¹, Hardeep Singh, MD, MPH², Sarah L. Krein, PhD, RN¹, Grace Y. Chen, MD, PhD¹, Amit G. Singal, MD, MS³, Jennifer Burns, MHS⁴, Kennedy Dubose, MPH⁴, Van Tony, MS⁴, Sameer D. Saini, MD, MS¹, Akbar Waljee, MD, MS¹. P4161 - Diagnosis of GI Tract Cancers in New Onset Iron Deficiency Anemia in a National Retrospective Cohort (2005-2019), ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.