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

BACKGROUND

Anemia 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.

METHODS

To 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 <9g/dL and no extraintestinal bleeding.

RESULTS

4552 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).

CONCLUSION

Not only GIC but also diffuse angiodysplasias caused the most severe anemia in IDA with predefined hemoglobin values <9g/dL.

Haemoglobin responses to transfusion in severe iron deficiency anaemia: potential impact of gastrointestinal disorders

BACKGROUND AND OBJECTIVES

Red blood cell (RBC) transfusion may be justified in iron deficiency anaemia (IDA) when an increase in oxygen delivery is needed, as sometimes occurs in subjects with haemoglobin <8·0 mg/dL, serious comorbidities or at risk of cardiovascular instability. Earlier investigations showed that some patients with severe IDA requiring transfusion had lower than expected post-transfusion haemoglobin levels with poorer clinical outcomes than other patients. After hypothesizing that haemoglobin responses to transfusion were different and that the underlying gastrointestinal (GI) disorders causing IDA could be a confounder explaining this association, these responses were analysed in a prospective cohort of IDA adults referred for outpatient GI investigation.

MATERIALS AND METHODS

Transfused patients with proven IDA, baseline haemoglobin at referral <9·0 g/dL and no extraintestinal bleeding were eligible. To assess a homogeneous population, only GI disorders known to cause occult bleeding were considered. Haemoglobin increments per 100 mL of RBCs were investigated.

RESULTS

In total, 2818 patients were enrolled over 10·5 years. On multivariable regression, diffuse angiodysplasias and GI cancer independently predicted for reduced increments in post-transfusion haemoglobin [adjusted regression coefficients: -0·082 (95% confidence interval, -0·093 to -0·072) and -0·073 (95% confidence interval, -0·081 to -0·066), respectively, P < 0·001 in both]. Haemoglobin responses in the remaining bleeding disorders were adequate and agreed with the principle that one RBC unit increases the haemoglobin an average of 1 g/dL.

CONCLUSION

The potential differential impact of GI disorders on changes in haemoglobin levels after RBC transfusion could be useful for transfusing physicians, especially for diagnostic purposes.