A comprehensive evaluation of the gastrointestinal tract in iron-deficiency anemia with predefined hemoglobin below 9 mg/dL: A prospective cohort study

BackgroundAnemia is defined as hemoglobin below the cutoff of normal in studies examining the gastrointestinal (GI) tract in iron-deficiency anemia (IDA). Although the risk of GI cancer (GIC) increases as hemoglobin decreases, guidelines do not usually recommend hemoglobin thresholds for IDA investigation.MethodsTo elucidate whether underlying GI disorders explain the different hemoglobin values and clinical outcomes observed initially in IDA patients referred for GI workup, we prospectively investigated the diagnostic yield of a thorough GI examination in consecutive IDA adults with predefined hemoglobin <9 g/dL and no extraintestinal bleeding.Results4552 patients were enrolled over 10 years. 96% of 4038 GI lesions were consistent with occult bleeding disorders and 4% with non-bleeding disorders. Predominant bleeding disorders included upper GI ulcerative/erosive lesions (51%), GIC (15%), and angiodysplasias (12%). Diffuse angiodysplasias (45% of angiodysplasias) and GIC showed the lowest hemoglobin values (6.3 [1.5] and 6.4 [1.3] g/dL, respectively). While the spread (diffuse vs. localized) and number (<3 vs. ≥3) of angiodysplasias correlated with the degree of anemia, hemoglobin values were lower in GIC with vs. without ulcerated/friable lesions (6.0 [1.1] vs. 7.0 [1.2] g/dL, P < 0.001).ConclusionNot only GIC but also diffuse angiodysplasias caused the most severe anemia in IDA with predefined hemoglobin values <9 g/dL.