HbA1c or fructosamine on evaluating glucose intolerance in children with beta- thalassemia.

BACKGROUND: Beta-thalassemia major (β-TM) patients are more likely to experience blood glucose intolerance and to date; the blood markers that could evaluate this are debatable. So, this study aimed to assess the roles of glycated hemoglobin A1c (HbA1c) and fructosamine in evaluating glucose intolerance in children with β-TM and figuring out role of insulin resistance in these patients.

METHODS: One hundred children diagnosed with β-TM and 100 age and sex-matched controls were enrolled. Fasting plasma glucose (FPG), 2-h post-prandial blood glucose (2-h PG), HbA1c, fructosamine, fasting insulin level (FINS), insulin resistance index (HOMA-IR), and insulin sensitivity index (HOMA-IS) were evaluated.

RESULTS: FPG and 2-h PG revealed glucose intolerance in 51 patients (51%), 19 of them had diabetes mellitus. HbA1c, fructosamine, FINS, and HOMA-IR showed a high statistically significant increase in patients compared to controls, (P < 0.001). Results revealed fructosamine was more specific in detecting prediabetes state and more sensitive in identifying diabetes mellitus in our patients when compared to HbA1c.

CONCLUSIONS: Despite controversies on HbA1c in children with β-TM, it is still valuable in glucose intolerance detection. Fructosamine showed more sensitivity and specificity. Furthermore, insulin resistance was prevalent in children with β-TM highlighting the necessity of regular glycemic state evaluation.

IMPACT: Glucose intolerance is a common complication in beta thalassemia patients. Conflicting data was reported about the role of HbA1c and fructosamine in evaluating glucose intolerance in thalassemic patients. Fructosamine does not yet have a threshold that may be used to distinguish between patients who have diabetes mellitus and those who do not. Fructosamine was more specific in detecting blood glucose intolerance compared to HbA1c and was more sensitive for diagnosing diabetes mellitus. Insulin resistance was common in patients with beta-thalassemia and often present before the onset of overt diabetes.