Glucose Metabolism and Insulin Response to Oral Glucose Tolerance Test (OGTT) in Prepubertal Patients with Transfusion-Dependent β-thalassemia (TDT): A Long-Term Retrospective Analysis

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 retrospective study of glucose homeostasis, insulin secretion, sensitivity/resistance in non- transfusion-dependent β-thalassemia patients (NTD- β Thal): reduced β-cell secretion rather than insulin resistance seems to be the dominant defect for glucose dysregulation (GD)

AIMS

Non-transfusion - dependent β-thalassemias (NTD-βThal) can cause iron overload and serious iron-related organ complications as endocrine dysfunction, including glucose dysregulation (GD).

PATIENTS AND METHODS

We retrieved data of all NTD- β Thal patients referred consecutively to a single Outpatient Italian Clinic from October 2010 to April 2023. All patients underwent a standard 3-h oral glucose tolerance test (OGTT) for analysis of glucose homeostasis, insulin secretion and sensitivity/resistance (IR), using conventional surrogate indices derived from the OGTT. The collected data in NTD- β Thal patients were compared to 20 healthy subjects.

RESULTS

Seventeen of 26 (65.3 %) NTD- β Thal patients (aged: 7.8 -35.1 years) had normal glucose tolerance, 1/26 (3.8 %) had impaired fasting glucose (IFG), 5/26 (19.2 %) impaired glucose tolerance (IGT), 1/26 (3.8%) IFG plus IGT and 2/26 (7.6%) plasma glucose (PG) level ≥155 mg/dL 1-h after glucose load. GD was observed exclusively in young adult patients; none of them had diabetes mellitus (DM). These findings were associated with a low insulinogenic index (IGI) and oral disposition index. HOMA-IR and QUICKI were not significantly different compared to controls. Interestingly, in young adult patients, ISI-Matsuda index was statistically higher compared to the control group, suggesting an increased insulin sensitivity.

CONCLUSIONS

This study reported a high prevalence of GD in young adults with NTD- β Thal. The documented reduction of IGI rather than the presence of IR, indicates reduced insulin secretory capacity as the pathophysiological basis of dysglycemia that may represent a novel investigational path for future studies on the mechanism(s) responsible for GD in NTD- β Thal 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.

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.

Glucose Homeostasis and Assessment of β-Cell Function by 3-hour Oral Glucose Tolerance (OGTT) in Patients with β-Thalassemia Major with Serum Ferritin below 1,000 ng/dL: Results from a Single ICET-A Centre

Aims

The primary aim of this study was to evaluate retrospectively the glucose homeostasis and surrogate indices of insulin sensitivity and resistance, during a 3-hour oral glucose tolerance test (OGTT), in β-thalassemia major patients (β-TM) with serum ferritin (SF) below 1,000 ng/mL.

Patients and methods

The retrospective cohort study evaluated the medical records of 24 β-TM patients from 2010 to 2022. At the year of study the mean age of patients was 31.0 ± 4.1 (20-37.11) years; 13 (54.1%) were females. The most commonly used iron chelator was deferoxamine (DFO: 75%), followed by deferiprone (DFP:12.5%) and deferasirox (DFX: 12.5%). Insulin sensitivity and resistance indices were derived from OGTT. A liver iron concentration (LIC) < 3 mg/g d.w. and a global heart T2* value > 20 ms were considered as conservative cut-off values for insignificant iron overload (IOL).

Results

The mean SF levels in the whole study cohort population at the age of evaluation was 549.6 ± 232.3 ng/mL. Based on the SF levels, two groups were identified: Group A (N = 14) < 500 ng/mL and Group B (N=10) 500-1,000 ng/mL. Normal glucose tolerance (NGT) during OGTT was observed in 4 patients of Group A (28.5 %) and in 5 patients of Group B (50%) (P: 0.29). The remaining 15/24 patients (62.5%) had glucose dysregulation (GD). The mean age at starting iron chelation therapy (ICT) and the mean SF peak in Group A versus Group B were significantly higher in group A. The GD was associated with significantly attenuated IGI (first phase of insulin response) and impaired oral disposition index (oDI). Hypogonadotropic hypogonadism (HH) was the most common associated endocrine complication in both groups of patients.

Conclusions

This study showed that efficient iron chelation monotherapy in patients with β-TM and SF < 1,000 ng/ml did not entirely prevent glucose metabolism disorders, abnormalities of insulin secretion and sensitivity, and development of acquired hypogonadism.

Screening for glucose dysregulation in β-thalassemia major (β-TM): An update of current evidences and personal experience

Glucose dysregulation (GD) in patients with β-thalassemia major (β-TM) usually develops gradually. Prediabetes consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), the latter detected by a standardized oral glucose tolerance test (OGTT). Diagnosis of prediabetes is essential for an early identification of high-risk individuals who will benefit from intensive iron chelation therapy and lifestyle modification. Therefore, patients with β-TM should undergo annual screening for glucose abnormalities, according to international recommendations, starting from the age of 10 years. OGTT remains the preferred screening method as it is more sensitive for GD than fasting plasma glucose (FPG), although it is poorly reproducible. The use of HbA1c measurement has limited use as it is generally considered unreliable in patients with thalassemia. Continuous glucose monitoring system (CGMS) is an accurate method to detect the variability of glucose fluctuations and offers the opportunity for better assessment of glucose homeostasis in a selected group of β-TM patients. Pancreatic Magnetic Resonance Imaging (MRI) associated with insulin secretion-sensitivity index-2 (ISSI-2) could be a complementary test, minimizing the necessity for OGTT and identifying high-risk patients before irreversible pancreatic damage occurs. The aims of this short report are to give practical guidance for an early identification of GD in β-TM patients, to summarise our experience, and to offer an impetus for further research in the field.

The The use of oral glucose-lowering agents (GLAs) in β-thalassemia patients with diabetes: Preliminary data from a retrospective study of ICET-A Network

OBJECTIVE

The management of prediabetes and hyperglycemia is an increasingly important aspect of care in patients with thalassemia. In light of the limited evidence about the management of GD (glucose dysregulation) with glucose-lowering agents (GLAs), we have conducted a retrospective survey in TDT and NTDT patients with diabetes mellitus to collect more detailed information on GLA use in order to make preliminary recommendations.

STUDY DESIGN AND METHOD

A questionnaire was prepared and distributed to the tertiary thalassemia care Centers of ICET-A Network.

RESULTS

Eight  thalassemia care Centers [Bulgaria, Greece, Iran, Italy (4 Centers) and Qatar], following 1.554 with transfusion-dependent thalassemia (TDT), 132 (8.4%) with diabetes and 687 with non-transfusion-dependent thalassemia (NTDT), 27 (3.9%) with diabetes, participated in the retrospective survey. The records of 117 TDT patients and 9 NTDT patients with diabetes treated with GLAs were analyzed. Metformin, a biguanide, was the most frequently used drug (47.6 %), followed by alpha-glucosidase inhibitors (5.5 %), incretins (4.7%) and insulin secretagogues (3.1%).  In 68 (61.2) patients  GLAs was prescribed as monotherapy, while the remaining  49  (38.8%), who had inadequate glucose control with metformin, were treated with combination treatment. Fifty-one patients  of 126 (40.4%) initially treated with oral GLA, for a mean duration of 61.0 ± 35.6 months (range: 12- 120 months), required insulin therapy for better metabolic control.

CONCLUSION

This retrospective study covers an unexplored area of research in patients with thalassemia and GD. Oral GLAs appear to be safe and effective for the treatment of diabetes mellitus in patients with thalassemia, and can achieve adequate glycemic control for a substantial period of time.

The evolution of glucose-insulin homeostasis in children with β-thalassemia major (β -TM): A twenty-year retrospective ICET- A observational analysis from early childhood to young adulthood

BACKGROUND

Thalassemia guidelines recommend oral glucose tolerance test (OGTT), starting from the age of 10 years, or earlier in the presence of iron overload.

OBJECTIVE

The aim of this retrospective study was to review and document the changes of glucose-insulin homeostasis from early childhood to young adulthood in β-thalassemia major (β -TM) patients with impaired fasting glucose (IFG) and normal OGTT.

METHODS

All data of the clinical patients' records of 18 β -TM patients' from September 1983 to September 2021 were included in the study. Annual or biennial OGTT results, for a duration of 15-20 years, were available for all patients.

RESULTS

The main findings are: a) IFG in children with β -TM represents a risk factor for the development of glucose dysregulation (GD) at later age; b) fluctuations of glucose homeostasis during follow-up were observed mainly in β-TM patients with IFG at baseline; and c) the primary defect of GD appears to be a low degree insulin resistance (IR), as estimated by HOMA-IR, followed by an insulin secretion defect.

CONCLUSION

These results are noteworthy as they revealed that firstly, the baseline IFG predicts future development of GD, and secondly, that almost half of patients with IFG at the outset had normal glucose handling 15 years later. Understanding the sequence of abnormalities in the progression from normal glucose homeostasis to GD and identifying the risk factors for the glycometabolic defects in thalassemic patients might help in the formulation of interventions.

Evolution of Combined Impaired Fasting Glucose and Impaired Glucose Tolerance in β-Thalassemia Major: Results in 58 Patients with a Mean 7.7- year Follow-Up

BACKGROUND

Advances in β- thalassemia major (β-TM) care have transformed a disease which had previously led to an early childhood death into a chronic condition. With increased lifespan, comorbidities associated with the disease have become more common, among them glucose dysregulation (GD) which develops insidiously, aggravating prognosis and patients' quality of life.

OBJECTIVES

The objectives of this study were to retrospectively review the extent to which β-TM patients, having combined impaired fasting glucose (IFG) and impaired glucose tolerance test (IGT) on oral glucose tolerance test (OGTT), progressed to diabetes and to analyze the potential determinants inducing this progression, or regression to normal glucose tolerance test (NGT).

RESEARCH DESIGN AND METHOD

Data of 58 β-TM patients, followed for a mean duration of 7.7 years (range: 1-20 years) with annual or biennial OGTT, were retrieved. Insulin release and insulin sensitivity (IS) were also analyzed.

RESULTS

During the follow-up, FPG and 2-h PG levels after OGTT reverted to NGT in 13 patients (22.4%), deteriorated in 13 patients (22.4%) who developed diabetes mellitus, and did not change in the remaining 32 patients (55.2%). A significant correlation was observed between FPG and ALT level (r: 0.3158; P:0.01) and an inverse correlation was found between chronological age and serum ferritin (SF) level (r: -0.321; P:0.014). Finally, SF and ALT, both at the baseline and at the time of last observation, were independent predictors of evolution to diabetes mellitus.

CONCLUSION

The combination IFG/IGT in β-TM patients with severe iron overload constitutes a high-risk state for developing diabetes.