Case Study: using a continuous glucose monitoring system in a patient with diabetes and beta-thalassemia hemoglobinopathy

The real-life management of glucose homeostasis abnormalities in pediatric onco-hematological diseases: data from a national survey

Glycemic abnormalities are a frequent finding in pediatric oncological patients, both during treatment and after its discontinuation. Moreover, impaired glucose tolerance (IGT), impaired fasting glycemia (IFG) and diabetes mellitus (DM) are not rarely diagnosed in non-oncological hematological diseases. To explore the current pediatric Italian approach to the diagnosis and the management of the glycemic alterations in this clinical setting and, thus, to identify and enforce current clinical needs, we submitted an online 23-items survey to all the Italian Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers, and surveys were descriptively analyzed. Thirty-nine AIEOP centers were involved in the study. In 2021, among 75278 children and adolescents affected by an oncological or a hematological disease, 1.2 and 0.65% developed DM, while IGT or IFG were widespread in 2.3 and 2.8%, respectively. The main causes of DM were the use of corticosteroids in patients with cancer and the iron overload in patients with thalassemia. Venous fasting plasma glycemia was the most used tool to detect glycemic abnormalities. The performance of oral glucose tolerance test (OGTT) was extremely limited, except when IFG occurred. Despite the diagnosis of DM, ∼45% of patients with cancer and 30% of patients with one hematological disease did not receive an appropriate treatment. In the other cases, insulin was the drug of first choice. Emerging technologies for diabetes care (glucose sensors and insulin pumps) are not largely used yet. The results of our study support the standardization of the care of the glycemic abnormalities during or after onco-hematologic diseases in the pediatric age. Despite the scarce data in pediatric literature, proper guidelines are needed.

Evaluation of continuous glucose monitoring system for detection of alterations in glucose homeostasis in pediatric patients with β-thalassemia major

BACKGROUND

Disturbances of glucose metabolism are common in β-thalassemia major (β-TM).

AIM

This study was conducted to assess the pattern of glucose homeostasis in pediatric β-TM patients comparing oral glucose tolerance test (OGTT) and continuous glucose monitoring system (CGMS).

METHODS

Two-hundred β-TM patients were studied and those with random blood glucose (RBG) ≥7.8 mmol/L (140 mg/dL) were subjected to OGTT, insertion of CGMS and measurement of fasting C peptide, fasting insulin, and hemoglobin A1c (HbA1c).

RESULTS

Twenty patients (10%) had RBG ≥ 7.8 mmol/L. Using OGTT, 6 out of 20 patients (30%) had impaired glucose tolerance (IGT) while 7 (35%) patients were in the diabetic range. CGMS showed that 7/20 (35%) patients had IGT and 13 (65%) patients had diabetes mellitus (DM); 10 of the latter group had HbA1c readings within diabetic range. The percentage of diabetic patients diagnosed by CGMS was significantly higher than that with OGTT (P = 0.012). Serum ferritin was the only independent variable related to elevated RBG. All β-TM patients with DM were non-compliant to chelation therapy.

CONCLUSIONS

The use of CGMS in the diagnosis of early glycemic abnormalities among pediatric patients with β-TM appears to be superior to other known diagnostic modalities.

The ICET-A Recommendations for the Diagnosis and Management of Disturbances of Glucose Homeostasis in Thalassemia Major Patients

Iron overload in patients with thalassemia major (TM) affects glucose regulation and is mediated by several mechanisms. The pathogenesis of glycaemic abnormalities in TM is complex and multifactorial. It has been predominantly attributed to a combination of reduced insulin secretory capacity and insulin resistance. The exact mechanisms responsible for progression from norm glycaemia to overt diabetes in these patients are still poorly understood but are attributed mainly to insulin deficiency resulting from the toxic effects of iron deposited in the pancreas and insulin resistance. A group of endocrinologists, haematologists and paediatricians, members of the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescence Medicine (ICET-A) convened to formulate recommendations for the diagnosis and management of abnormalities of glucose homeostasis in thalassemia major patients on the basis of available evidence from clinical and laboratory data and consensus practice. The results of their work and discussions are described in this article.