Soluble transferrin receptor level: a new marker of iron deficiency anemia, a common manifestation of gastric autoimmunity in type 1 diabetes.
OBJECTIVE: A total of 15-20% of type 1 diabetic patients have parietal cell antibodies (PCAs). PCA+ subjects are at increased risk for iron deficiency anemia and atrophic gastritis. Recently, soluble transferrin receptor (sTfR) levels have proven to be a sensitive indicator for iron deficiency They are, in contrast with ferritin levels, independent of inflammation, liver and hormonal status, and sex. We are the first to evaluate sTfR levels in type 1 diabetes and tested the hypothesis of higher sTfR levels in patients with PCAs and/or autoimmune gastritis. RESEARCH DESIGN AND METHODS: We examined 148 type 1 diabetic patients (85 men and 63 women; 50 were PCA+) and 59 sex- and age-matched control subjects (30 men and 29 women). The main outcome measures were sTfR levels, iron deficiency anemia, and atrophic gastritis. Logistical regression analysis tested risk factors for iron deficiency RESULTS: Iron deficiency was present in 38 subjects. Iron (P<0.0001) and ferritin (P<0.0001) levels but not sTfR levels were lower in women. sTfR levels were similar in diabetic and control subjects but were higher in PCA+ subjects (P = 0.015). In diabetic subjects, iron deficiency anemia was more prevalent in PCA+ than in PCA- patients (odds ratio 3.07, P = 0.013) and was associated with sex (P = 0.0001), age (P = 0.046), and sTfR (P = 0.0008) levels. Atrophic gastritis was present in 15 of 28 PCA+ and in 1 of 11 PCA diabetic subjects (P = 0.014). sTfR levels tended to be higher in patients with atrophic gastritis (P = 0.062). CONCLUSIONS: In type 1 diabetes, sTfR levels can be used to diagnose iron deficiency anemia, which is more prevalent in PCA+ subjects. sTfR levels are higher in PCA+ individuals who are at risk for developing atrophic gastritis.