Elevated iron indices in patients with diabetes

Aims: Excess iron has been implicated in the pathogenesis of diabetes and its complications. This study documents the assessment of plasma iron indices and the correlation between transferrin saturation with biochemical and clinical parameters in a cross-sectional survey of 820 patients with diabetes in long-term follow-up in a single clinic. Methods: Plasma iron indices, together with the biochemical and clinical profile of all patients, were recorded over a 2-year period. Predictors of the transferrin saturation were identified using multiple and logistic regression analysis. Results Eighty per cent of patients had Type 2 diabetes. The prevalence of elevated transferrin saturation (> 35%) was 3-4-fold higher in patients with diabetes, compared with historical prevalence described in the general population. Independent associations with elevated transferrin saturation were male gender, low C-reactive protein, and increased fasting plasma glucose (all P < 0.0001). Patients with Type 1 diabetes were also more likely to have an elevated transferrin saturation [odds ratio 3.9 (95% CI 1.9-8.0), P < 0.001]. Patients with an elevated transferrin saturation were younger, but had a similar duration of diabetes, possibly suggesting an earlier age of onset. There was no correlation between the presence of diabetic complications and the presence of elevated iron indices. Conclusions: Elevated iron indices are more common in patients with diabetes. Excess iron may have a role in the development of diabetes and subsequently in glycaemic control. This should be balanced by the strong association between iron indices and anaemia in patients with diabetes.