Aims: To audit our experience with gastrointestinal investigation of iron deficiency anemia (IDA) and assess whether gastric atrophy associates with and likely causes it.
Methods: This is a case-control study in a large U.K. teaching hospital. In total, 161 unselected patients undergoing routine investigation for iron deficiency anemia were submitted for the study, of which 5 were excluded for lack of appropriate biopsies. In total, 169 patients identified retrospectively from pathology records who had appropriate biopsies with a normal hemoglobin and no evidence of iron deficiency constituted the control group. In the group with anemia, a further internal case-control study compared cases where no definite cause for anemia was detected with controls who had a definite accepted cause for anemia. The gastric pathology, especially the presence and degree of body atrophy, was assessed by a single pathologist in both groups. Other factors including age, sex, and Helicobacter pylori infection were also evaluated.
Results: The mean age of the cases was 68 yr (95% confidence interval [CI] 34-102), and for the controls, it was 53 yr (95% CI 19-87). In the patients with anemia, 40 of 156 (25.6%) had significant body atrophy compared with just 7 of 169 (4.6%) of controls (P < 0.001). In a multivariate analysis, only significant body atrophy, odds ratio (OR) of 7.6 (3.1-18.6), and age, OR 1.048/yr (1.032-1.064), emerged as significant factors predicting anemia. In the cases, 35 of 156 (22%) patients had another definite cause of anemia. Of these, only 3 of 35 (9%) had significant atrophy, significantly less than the 37 of 121 (31%) without another definite cause (P = 0.008). In this anemic group, there was no difference in age between those with and without atrophy.
Conclusions: Gastric atrophy is strongly associated with IDA, and this is likely to be causative in some patients and contributory in others. Gastric biopsies, especially from the corpus, may provide valuable information in the investigation of IDA.