Prevalence of genetic hemochromatosis in a cohort of Italian patients with diabetes mellitus

Background: Few data exist on the prevalence of genetic hemochromatosis among diabetic patients. Objective: To compare the prevalence of genetic hemochromatosis in diabetic patients and a matched control group and to evaluate the accuracy of iron-related indexes in detecting hemochromatosis. Design: Cross-sectional study. Setting: Diabetes clinics of four hospitals in northern Italy. Patients: 894 diabetic patients (117 with type 1 diabetes and 777 with type 2 diabetes) and 467 matched controls. Measurements: Transferrin saturation and serum ferritin levels were measured in all study participants. After secondary iron overload was excluded as the cause of persistently elevated transferrin saturation and serum ferritin levels, liver biopsy was performed and siderosis was estimated semiquantitatively and quantitatively. A hepatic iron index greater than 1.9 was considered diagnostic for hemochromatosis. Results: Hemochromatosis was diagnosed in 12 patients with type Z diabetes (prevalence, 1.34% [95% CI, 0.7% to 2.3%]) and 1 control (prevalence, 0.2% [CI, 0.1% to 1.4%]; P = 0.032). The odds ratio of hemochromatosis in association with diabetes was 6.3 (CI, 1.1 to 37.7). Measurement of transferrin saturation was the most sensitive test for hemochromatosis. Conclusions: Genetic hemochromatosis is frequently not diagnosed in patients with diabetes, although it is a hallmark of the disease. Screening for hemochromatosis could be beneficial for patients with diabetes.