Insulin-Like Growth Factor -1 (IGF-1) and Glucose Dysregulation in Young Adult Patients with β-Thalassemia Major: Causality or Potential Link?

Endocrinopathies in beta thalassemia: a narrative review

Beta thalassemia is the most common genetic blood disorder, characterized by reduced production or complete absence of beta-globin chains. The combination of systematic red blood cell transfusion and iron chelation therapy is the most readily available supportive treatment and one that has considerably prolonged the survival of thalassemia patients. Despite this, the development of endocrine abnormalities correlated with beta thalassemia still exists and is mostly associated with iron overload, chronic anemia, and hypoxia. A multifactorial approach has been employed to investigate other factors involved in the pathogenesis of endocrinopathies, including genotype, liver disease, HCV, splenectomy, socioeconomic factors, chelation therapy, and deficiency of elements. The development of specific biomarkers for predicting endocrinopathy risk has been the subject of extensive discussion. The objective of the present narrative review is to present recent data on endocrinopathies in beta thalassemia patients, including the prevalence, the proposed pathogenetic mechanisms, the risk factors, the diagnostic methods applied, and finally the recommended treatment options.

Can we Predict Incipient Diabetes Mellitus in Patients with Transfusion Dependent β-Thalassemia (β-TDT) Referred with a History of Prediabetes?

Background

Prediabetes and diabetes mellitus (DM) are complications in adult patients with transfusion-dependent β-thalassemia (β-TDT), with their incidence increasing with age.

Objective

This retrospective observational study describes the glycemic trajectories and evaluates predictive indices of β-cell function and insulin sensitivity/resistance in β-TDT patients with prediabetes, both in a steady state and during 3-h oral glucose tolerance test (OGTT), in order to identify patients at high risk for incipient diabetes.

Setting

The study was mainly conducted at the Pediatric and Adolescent Outpatient Clinic, Quisisana Hospital, Ferrara (Italy), in collaboration with thalassemia referring centers across Italy.

Patients

The study included 11 β-TDT (aged 15.11-31.10 years) with prediabetes. Methods: The ADA criteria for the diagnosis of glucose dysregulation were adopted. Investigations included evaluating plasma glucose levels and insulin secretion, analyzing glycemic trajectories and indices of β-cell function, and insulin sensitivity/resistance assessed in steady state and during OGTT.

Results

The duration of progression from prediabetes to DM, expressed in years, showed a positive direct correlation with corrected insulin response (CIR-30 = r: 0.7606, P: 0.0065), insulinogenic index (IGI 0-120 = r: 0.6121, P:0.045), oral disposition index (oDI = r: 0.7119, P:0.013), insulin growth factor-1 (IGF-1= r: 0.6246, P: 0.039) and an inverse linear correlation with serum ferritin (SF = r: -0.7197, P: 0.012). The number of patients with 1-hour post-load PG value ≥ 155 mg/dL ( ≥ 8.6 mmol/L) was at -4 years: 4/9 (44.4%); -3 years: 8/9 (88.8%); - 2 years: 7/10 (70 %) and at -1 year: 11/11 (100%) (PG range:162-217 mg/dL).

Conclusions

A progressive increase in 1-hour PG in response to OGTT is associated with progressive β-cell failure, peripheral resistance to insulin action, and reduced oDI and may be considered a relevant marker for incipient DM in β-TDT patients with prediabetes.

A prospective guide for clinical implementation of selected OGTT- derived surrogate indices for the evaluation of β- cell function and insulin sensitivity in patients with transfusion-dependent β- thalassaemia

The gold standard for the measurement of insulin secretion is the hyperglycemic clamp and for insulin sensitivity the hyperinsulinemic euglycemic clamp, respectively. A number of surrogate indices, derived from plasma glucose and insulin levels at a fasting state or after oral glucose load, have been proposed to estimate β-cell response, and the ability of β-cells to compensate for changes of insulin sensitivity by modulating insulin secretion (disposition index). Starting from the current recommendations for the annual screening of glucose dysregulation in patients with transfusion dependent β-thalassemia (β-TDT), this article summarizes the most frequently used indirect indices of insulin secretion and resistance derived from the oral glucose tolerance test (OGTT) and discusses the strengths and weaknesses of selected indices and the basic concepts underlying each method for the appropriate evaluation of glucose regulation. Basal indices for β-cell function and insulin sensitivity, albeit simple and cheap, have limited usefulness due to a high coefficient variation and the lack of data about response to glucose load. Therefore, measurement of indices during an OGTT, despite being costly and time-consuming, is suggested since it can detect, even subtle, dynamic changes in insulin secretion and glucose handling. In patients with β-TDT, the indices derived from OGTT may offer an additional factor to evaluate the efficiency of iron chelation therapy and detect patients who may need intensification of iron chelation therapy and/or pharmacological intervention.

The effects of excess weight on glucose homeostasis in young adult females with β-thalassemia major (β-TM): a preliminary retrospective study

BACKGROUND

With the rising prevalence of obesity worldwide, it is becoming imperative to detect disturbed glucose metabolism as early as possible in order to prevent type 2 diabetes (T2D) development.

STUDY DESIGN

The present retrospective observational study aimed to evaluate the relationship between BMI and glucose metabolism, insulin secretion and sensitivity indices, derived from glucose tolerance test (OGTT), in β -TM female patients who were overweight (BMI 25-29.9 kg/m2) and follow its outcome over time.

SUBJECTS AND METHODS

Eleven overweight and 11 females with ideal weight and β -TM, matched for age, were recruited. OGTT was undertaken and different indices for β-cell function, insulin sensitivity and insulin secretion were calculated.

RESULTS

At first evaluation, 7 of 11 overweight β -TM patients (63.6%) and 3 of 11 normal weight β-TM patients (27.2%) had glucose dysregulation (GD) during OGTT. Overweight patients with β-TM had increased HOMA-IR and QUICKI indices associated with decreased Matsuda WBISI index. The mean ± SD duration of follow-up was 4.5 ± 1.2 years. At last observation, 2/11 overweight patients had developed T2D (18.1%). In patients with normal weight, GD increased from 3/11 (27.2%) to 5/11 (45.4%), but none developed T2DM. The difference between SF at first and last observation (1,220 ± 702 vs.1,091 ± 454 ng/mL; P: 0.61) was not significant.

CONCLUSION

Overweight seems to be an additional risk factor for the development of GD in β-TM patients. This is particularly important in clinical practice, due to the lack of appropriate guidelines dedicated to this group of patients.

The effects of excess weight on glucose homeostasis in young adult females with β-thalassemia major (β-TM): a preliminary retrospective study

BACKGROUND

With the rising prevalence of obesity worldwide, it is becoming imperative to detect disturbed glucose metabolism as early as possible in order to prevent type 2 diabetes (T2D) development.

STUDY DESIGN

The present retrospective observational study aimed to evaluate the relationship between BMI and glucose metabolism, insulin secretion and sensitivity indices, derived from glucose tolerance test (OGTT), in β -TM female patients who were overweight (BMI 25-29.9 kg/m2) and follow its outcome over time.

SUBJECTS AND METHODS

Eleven overweight and 11 females with ideal weight and β -TM, matched for age, were recruited. OGTT was undertaken and different indices for β-cell function, insulin sensitivity and insulin secretion were calculated.

RESULTS

At first evaluation, 7 of 11 overweight β -TM patients (63.6%) and 3 of 11 normal weight β-TM patients (27.2%) had glucose dysregulation (GD) during OGTT. Overweight patients with β-TM had increased HOMA-IR and QUICKI indices associated with decreased Matsuda WBISI index. The mean ± SD duration of follow-up was 4.5 ± 1.2 years. At last observation, 2/11 overweight patients had developed T2D (18.1%). In patients with normal weight, GD increased from 3/11 (27.2%) to 5/11 (45.4%), but none developed T2DM. The difference between SF at first and last observation (1,220 ± 702 vs.1,091 ± 454 ng/mL; P: 0.61) was not significant.

CONCLUSION

Overweight seems to be an additional risk factor for the development of GD in β-TM patients. This is particularly important in clinical practice, due to the lack of appropriate guidelines dedicated to this group of patients.

Assessment of glucose homeostasis in young adult female β-thalassemia major patients (β-TM) with acquired hypogonadotropic hypogonadism (AHH) never treated with sex steroids compared to eugonadal β-TM patients with spontaneous menstrual cycles

BACKGROUND

Acquired ypogonadotropic hypogonadism (AHH) is the most prevalent endocrine complication in thalassemia major (TM).

STUDY DESIGN

Considering the detrimental effect of estrogen deficiency on glucose metabolism, the ICET-A Network promoted a retrospective study on the long-term effects of estrogen deficiency on glucose homeostasis in female β-TM patients with HH without hormonal replacement therapy (HRT).

PATIENTS AND METHODS

Seventeen β-TM patients with AHH (4 had arrested puberty; Tanners' breast stage 2-3), never treated with sex steroids, and 11 eugonadal β-TM patients with spontaneous menstrual cycles at the time of referral were studied. A standard 3-h OGTT was performed in the morning, after an overnight fast. Six-point plasma glucose and insulin level determinations, indices of insulin secretion and sensitivity, early-phase insulin insulinogenic index (IGI), HOMA-IR and β-cell function (HOMA-β), oral disposition index (oDI), glucose and insulin areas under the OGTT curves were evaluated.

RESULTS

Abnormal glucose tolerance (AGT) or diabetes was observed in 15 (88.2%) of 17 patients with AHH and 6 (54.5%) of 11 patients with eumenorrhea. The difference between the two groups was statistically significant (P: 0.048). However, the group of eugonadal patients was younger compared to AHH patients (26.5 ± 4.8 years vs. 32.6 ± 6.2 years ; P: 0.010). Advanced age,  severity of iron overload, splenectomy, increased ALT levels and reduced IGF-1 levels were the main clinical and laboratory risk factors for glucose dysregulation observed in β-TM with AHH compared to eugonadal β-TM patients with spontaneous menstrual cycles.

CONCLUSION

These data further support the indication for an annual assessment of OGTT in patients with β-TM. We believe that a registry of subjects with hypogonadism is necessary for a better understanding of the long-term consequences of this condition and  refining treatment options.

Recent advancements in glucose dysregulation and pharmacological management of osteoporosis in transfusion-dependent thalassemia (TDT): an update of ICET-A (International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescence Medicine)

PURPOSE OF REVIEW

The aim of this short review is to provide an update on glucose homeostasis, insulin secretion and pharmacological management of osteoporosis in transfusion-dependent thalassemia (TDT).

RECENT FINDINGS

A retrospective study, documenting the changes in glucose-insulin homeostasis from early childhood to young adulthood, has advanced our understanding of the evolution of glucose regulation in patients with TDT. Magnetic Resonance Imaging (T2* MRI) is considered to be a reliable tool to measure pancreatic iron overload. Continuous glucose monitoring systems (CGMS) can be used in early diagnosis of glucose dysregulation and in disease management in patients with already diagnosed diabetes. Oral glucose-lowering agents (GLAs) are effective and safe for the treatment of diabetes mellitus (DM) in patients with TDT, achieving adequate glycemic control for a substantial period of time. Current modalities for the management of osteoporosis in adults with TDT include inhibitors of bone remodeling such as bisphosphonates and denosumab as well as stimulators of bone formation (e.g., teriparatide), Considering the unique characteristics of osteoporosis associated with TDT, early diagnosis, treatment initiation and treatment duration are critical issues in the management this special population.

CONCLUSIONS

Advances in the care of TDT patients  have led to improved survival and quality of life. Nevertheless, many chronic endocrine complications still remain. Their routine screening and a high index of suspicion are imperative in order to provide timely diagnosis and  treatment.