It is noted that patients with heart disease (HD) are likely to develop abnormal glucose metabolism and this metabolic deterioration usually occurs after middle age. However, we recently had two patients with congenital HD, who developed type 2 diabetes mellitus (DM) in their adolescence.The first patient underwent Fontan operation at 2 years of age for single ventricle and pulmonary atresia. His paternal grandfather had type 2 DM. He noticed polydipsia and polyuria at 15 years of age. His Body Mass Index (BMI) at that time was 13.87 kg/m2. Laboratory data revealed casual plasma glucose level of 562 mg/dl and HbA1c of 10.7 %. After obtaining normal glucose levels by insulin therapy, a glucagon challenge test was performed and exhibited peak C peptide value of 3.58 ng/ml. His islet autoantibody was negative. He was diagnosed as type 2 DM and insulin therapy was stopped. He has been treated with Metformin 1500mg a day and keeps HbA1c as low as 6-percent levels. The second case had Blalock-Taussig shunt procedure for tricuspid atresia, ventricular septal defect, and pulmonary artery stenosis during infancy. His great-grandparents had type 2 DM. At a regular visit of 14 years of age, it was pointed out that his HbA1c level was as high as 7.6%. His BMI was 14.22 kg/m2. An oral glucose tolerance test and islet autoantibody test indicated type 2 DM. His HOMA-R and insulinogenic index were 0.97 and 0.48, respectively. Metformin was started and increased to 1000mg per day, followed by Sitagliptin Phosphate Hydrate 50mg daily. His glycemic control is rather insufficient and HbA1c stays around 7%. Neither patients could perform adequate physical exercise for their age because of chronic heart failure, but they did not have risky daily habits of DM such as excessive intake of carbohydrates. Actually, they had not been obese through their life. There are some reports indicating higher incidence of type 2 DM or metabolic syndrome in adults with HD. Cyanosis, heart failure and hypoxia are speculated as contributing factors as these phenomena. However, the mechanisms are not clearly understood. Our cases indicate that for patients with congenital HD and those with chronic heart failure their metabolic status should be checked even in adolescence and young adult age.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology