Insulin-like growth factor- I and factors affecting it in thalassemia major

Disease burden, management strategies, and unmet needs in α-thalassemia due to hemoglobin H disease

Alpha-thalassemia is an inherited blood disorder caused by impaired α-globin chain production, leading to anemia and other complications. Hemoglobin H (HbH) disease is caused by a combination of mutations generally affecting the expression of three of four α-globin alleles; disease severity is highly heterogeneous, largely driven by genotype. Notably, non-deletional mutations cause a greater degree of ineffective erythropoiesis and hemolysis, higher transfusion burden, and increased complication risks versus deletional mutations. There are limited treatment options for HbH disease, and effective therapies are needed. This review discusses the pathophysiology of HbH disease, current management strategies, unmet needs, and emerging treatment options.

Very low serum IGF-1 levels are associated with vertebral fractures in adult males with beta-thalassemia major

PURPOSE

Patients with beta-thalassemia major (BTM) often develop several endocrine disorders due to chronic iron overload. They are also prone to osteoporosis and vertebral fractures. Plasmatic insulin-like growth factor-1 (IGF-1) levels are often low in subjects with BTM, which origin is multifactorial. The aim of this study was to evaluate a possible relationship between serum IGF-1 levels and the presence of osteoporosis and/or vertebral fractures.

METHODS

We retrospectively evaluated the occurrence of vertebral fractures in 30 adult male patients affected by BTM (mean age 43.3 ± 7.9 years) with low serum IGF-1 (median value 52.4 ng/ml, 38.5-83.4). Only 6 of them (20.0%) were diagnosed with GH deficiency (GHD) after GHRH/arginine stimulation test, while 23 (76.7%) had osteoporosis and 12 (40.0%) had known vertebral fractures. All patients except one also showed at least one endocrine disorder.

RESULTS

Serum IGF-1 was significantly lower in BTM patients with vertebral fractures compared to patients without vertebral fractures (U = 41.0, p = 0.005) while it was not significantly different between patients with low bone mass compared to patients without low bone mass. The diagnosis of GHD was significantly associated with lower serum IGF-1 (p = 0.001) and vertebral fractures (p = 0.002) but not with low bone mass. After ROC analysis, we found that very low IGF-1 (≤ 50.0 ng/dl) was associated with vertebral fractures (sensitivity 83.3%, specificity 75.0%) and was also predictive of GHD (sensitivity 75.0%, specificity 100.0%).

CONCLUSION

Our study shows that, in male patients with BTM, serum IGF-1 ≤ 50.0 ng/dl is a marker of vertebral fractures and it is predictive of a diagnosis of GHD.

Nutritional studies in patients with β-thalassemia major: A short review

BACKGROUND

Patients with β-thalassemia major (BTM) had variable prevalence of undernutrition and abnormal body composition.  Methods: We performed an electronic search in PubMed, Scopus, Research gate, and Web of Sciences to evaluate the prevalence of nutritional disorders in patients with BTM worldwide in relation to their body composition and possible etiological factors. In addition, we reviewed the published nutritional intervention studies.  Results: 22 studies on the prevalence of undernutrition (12 countries) and 23 nutritional intervention studies were analyzed.  Undernutrition occurred in a considerable number of patients but varied greatly among different countries (from 5.2% to 70%). The lower middle income (LMI) countries (India, Pakistan, Iran, Egypt) had higher prevalence, while (high -middle and high income (Turkey, Greece, North America, USA, Canada) had lower prevalence.  Even in patients with normal BMI, abnormalities of body composition are common with decreased muscle mass, lean-body mass, and bone mineral density. 65% to 75% of them had lower energy intake with low levels of circulating nutrients, minerals (zinc, selenium, and copper), and vitamins (D, E) versus controls. Increased macro and micronutrient requirements decreased absorption and /or increased loss or excretion are etiologic factors. Undernutrition was associated with short stature and lower quality of life (QOL). High prevalence of endocrinopathies, poor transfusion regimen (tissue hypoxia), improper chelation, and lack of maternal education, represented important risk factors in the production of poor growth in weight and stature.

CONCLUSIONS

Timely detection of undernutrition in patients with BTM and proper nutritional intervention could prevent growth delay and comorbidities.

Thermoprotective molecules: Effect of insulin-like growth factor type I (IGF-1) in cattle oocytes exposed to high temperatures

The adverse effects of heat stress (HS) on the welfare and productivity of cattle are the result of the associated hyperthermia and the physiological and behavioral mechanisms performed by the animal to regulate body temperature. The negative effects of HS on in vitro oocyte maturation and in vitro bovine embryo production have been reported; being one of the major concerns due to economic and productive losses, and several mechanisms have been implemented to reduce its impact. These mechanisms include supplementation of the medium with hormones, adjuvants, identification of protective genes, among others. This review aims to explore the cellular and molecular mechanisms of insulin-like growth factor-1 (IGF-1) during in vitro and in vivo maturation of bovine oocytes and its thermoprotective effect under HS. Although the supplementation of the culture medium during oocyte maturation with IGF-1 has been implemented during the last years, there are still controversial results, however, supplementation with low concentration showed a positive effect on maturation and thermoprotection of oocytes exposed to higher temperatures. Additionally, IGF-1 is involved in multiple cellular pathways, and it may regulate cell apoptosis in cases of HS and protect oocyte competence under in vitro conditions.

Approach to the management of β thalassemia major associated osteoporosis - A long-standing relationship revisited

Adults with β- thalassemia major (β-TM) develop low BMD and fragility fractures at a higher incidence and at a younger age compared to the general population. The disease itself, including direct effects of anemia and iron overload toxicity on bone turnover, genetic susceptibility, thalassemia-related endocrinopathies and acquittance of suboptimal peak bone mass contribute to low bone mass and increased bone fragility frequently encountered among these patients. Current management of osteoporosis requires long-term treatment that can be provided by agents that reduce the risk of all osteoporotic fractures by modulating bone metabolism with different mechanisms of action. These include inhibitors of bone remodeling (e.g., bisphosphonates, denosumab) and stimulators of bone formation (e.g., PTHR1 agonists and sclerostin antibodies). Considering the unique characteristics of osteoporosis associated with β-TM and the clinical importance of balancing the risk/benefit of treatment in the long-term, appropriate use of these therapeutic approaches is essential for patient care. In this review we outline current literature on the use of anti-osteoporotic drugs in β-TM patients with osteoporosis focusing on data on the efficacy, safety, and duration of treatment. In addition, we propose a long-term management plan for β-TM -associated osteoporosis aiming at the optimal patient care for this special population.

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

BACKGROUND

Insulin-like growth factor-1 (IGF-1) has been shown to lower blood glucose through stimulating glucose transport to fat and muscle and inhibiting hepatic glucose output. Although previous cross-sectional reports reported an association between low circulating concentrations of IGF-1 and glucose dysregulation (GD), its role is still debated.

AIMS OF STUDY

The present retrospective study was designed to assess the circulating IGF-1 levels in β-thalassemia major (β -TM) patients with normal oral glucose tolerance test (NGT-OGTT) and (GD) referred for an endocrine evaluation to explore the potential link between low IGF-1 and GD.

STUDY DESIGN AND METHODS

Our study included 34 young adult patients with β-TM; 12 patients with NGT after OGTT, 7 with impaired glucose tolerance (IGT), 9 with impaired fasting glucose (IFG) plus IGT, and 6 patients with β-TM-related diabetes mellitus (β-TM- DM).

RESULTS

Twenty-two β-TM patients with GD or β-TM- DM and 1 patient with NGT had IGF-1 levels below the 2.5th percentile. Correlation of IGF-1 with fasting plasma glucose, HOMA-IR (homeostatic model assessment for insulin resistance) and OGIS (oral glucose insulin sensitivity) was found. Moreover, a negative correlation was documented between ALT and the Insulinogenic Index (IGI) and a positive correlation between serum ferritin and PG 2-h after OGTT.

CONCLUSION

This study reports for the first time an association between low levels of IGF-1 and GD in β-TM patients. Despite some limitations, our study can serve to generate proposals for more convenient and efficient methods to identify and treat early GD in patients with β-TM, and to conduct more extensive studies. www.actabiomedica.it).

Fracture prevalence in thalassemia: a systematic review and meta-analysis

BACKGROUND

Multiple observational studies have reported high prevalence of fracture in patients with thalassemia. However, most of these studies have included limited number of patients, and only few of them have reported prevalence of fracture among patients with different types and severity of thalassemia.

OBJECTIVE

This systematic review and meta-analysis was conducted to summarize all available data of fracture prevalence among patients with thalassemia.

METHODS

A systematic review was conducted using EMBASE and MEDLINE databases from inception to June 2021 to determine studies that reported prevalence of fracture in thalassemia patients. The pooled prevalence with 95% confidence interval (95%CI) of fracture across studies was determined using a random-effect, generic inverse variance method.

RESULTS

After two rounds of systematic review, a total of 25 studies with 4934 patients were included in the meta-analysis. The pooled prevalence of fracture among patients with thalassemia was 16% (95%CI, 15-17%, I² = 94.3%). The subgroup analyses showed that the pooled prevalence of fracture was 4% (95%CI, 2-6%; I² = 70.4%) among patients with alpha thalassemia, 17% (95%CI, 16-19%; I² = 93.2%) among patients with beta thalassemia, 18% (95%CI, 16-19%; I² = 89.0%) among patients with transfusion-dependent thalassemia, and 7% (95%CI, 4-10%; I² = 94.2%) among patients with non-transfusion-dependent thalassemia.

CONCLUSION

Fracture is common in patients with thalassemia, and may be more prevalent in beta thalassemia and transfusion-dependent thalassemia than in alpha thalassemia and non-transfusion-dependent thalassemia.

Growth hormone therapy for people with thalassaemia

BACKGROUND

Thalassaemia is a recessively-inherited blood disorder that leads to anaemia of varying severity. In those affected by the more severe forms, regular blood transfusions are required which may lead to iron overload. Accumulated iron from blood transfusions may be deposited in vital organs including the heart, liver and endocrine organs such as the pituitary glands which can affect growth hormone production. Growth hormone deficiency is one of the factors that can lead to short stature, a common complication in people with thalassaemia. Growth hormone replacement therapy has been used in children with thalassaemia who have short stature and growth hormone deficiency. This review on the role of growth hormone was originally published in September 2017 and updated in April 2020.

OBJECTIVES

To assess the benefits and safety of growth hormone therapy in people with thalassaemia.

SEARCH METHODS

We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of latest search: 14 November 2019. We also searched the reference lists of relevant articles, reviews and clinical trial registries. Date of latest search: 06 January 2020.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing the use of growth hormone therapy to placebo or standard care in people with thalassaemia of any type or severity.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion. Data extraction and assessment of risk of bias were also conducted independently by two authors. The certainty of the evidence was assessed using GRADE criteria.

MAIN RESULTS

We included one parallel trial conducted in Turkey. The trial recruited 20 children with homozygous beta thalassaemia who had short stature; 10 children received growth hormone therapy administered subcutaneously on a daily basis at a dose of 0.7 IU/kg per week and 10 children received standard care. The overall risk of bias in this trial was low except for the selection criteria and attrition bias which were unclear. The certainty of the evidence for all major outcomes was moderate, the main concern was imprecision of the estimates due to the small sample size leading to wide confidence intervals. Final height (cm) (the review's pre-specified primary outcome) and change in height were not assessed in the included trial. The trial reported no clear difference between groups in height standard deviation (SD) score after one year, mean difference (MD) -0.09 (95% confidence interval (CI) -0.33 to 0.15 (moderate-certainty evidence). However, modest improvements appeared to be observed in the following key outcomes in children receiving growth hormone therapy compared to control (moderate-certainty evidence): change between baseline and final visit in height SD score, MD 0.26 (95% CI 0.13 to 0.39); height velocity, MD 2.28 cm/year (95% CI 1.76 to 2.80); height velocity SD score, MD 3.31 (95% CI 2.43 to 4.19); and change in height velocity SD score between baseline and final visit, MD 3.41 (95% CI 2.45 to 4.37). No adverse effects of treatment were reported in either group; however, while there was no clear difference between groups in the oral glucose tolerance test at one year, fasting blood glucose was significantly higher in the growth hormone therapy group compared to control, although both results were still within the normal range, MD 6.67 mg/dL (95% CI 2.66 to 10.68). There were no data beyond the one-year trial period.

AUTHORS' CONCLUSIONS

A small single trial contributed evidence of moderate certainty that the use of growth hormone for a year may improve height velocity of children with thalassaemia although height SD score in the treatment group was similar to the control group. There are no randomised controlled trials in adults or trials that address the use of growth hormone therapy over a longer period and assess its effect on final height and quality of life. The optimal dosage of growth hormone and the ideal time to start this therapy remain uncertain. Large well-designed randomised controlled trials over a longer period with sufficient duration of follow up are needed.

Final Height and Endocrine Complications in Patients with β-Thalassemia Intermedia: Our Experience in Non-Transfused Versus Infrequently Transfused Patients and Correlations with Liver Iron Content

BACKGROUND

β-thalassemia intermedia (TI) spans a wide spectrum of severity and carries higher morbidity than previously recognized, including extramedullary hematopoiesis, leg ulcers, gallstones, thrombosis, secondary heart failure, pulmonary hypertension, skeletal deformity, growth retardation and endocrine abnormalities, such as diabetes mellitus, hypothyroidism, osteoporosis, and hypogonadism.

OBJECTIVES

To evaluate the final height and the endocrine complications encountered in young adult patients with TI followed at Hematology Section, Doha (Qatar) in relation to liver iron content in non-transfused versus infrequently transfused TI patients.

PATIENTS AND METHODS

This retrospective cohort study was performed on 28 young adults with TI who were randomly selected from the Hematology Clinic of the Hematology Section, National Centre for Cancer Care and Research, Hamad Medical Corporation of Doha (Qatar).Eligibility criteria for this retrospective analysis included TI patients diagnosed by complete blood count, hemoglobin electrophoresis and young adult age ( ≥ 18 years).Group 1 included nine patients who did not receive any blood transfusion, and Group 2 included 19 patients who infrequently received blood transfusions.Data recorded from charts included demographic characteristics (gender, date of birth, ethnicity), disease and treatment characteristics (e.g., transfusion frequency, history of chelation therapy, and splenectomy), auxological and pubertal data [growth percentiles and pubertal stages, and body mass index (BMI)], laboratory data and target organ complications (including endocrinopathies and liver disease). Iron overload was assessed by direct (liver iron content; LIC) and indirect methods (SF), and bone mass index (BMA) by dual-energy X-ray absorptiometry (DXA).

RESULTS

Short stature [Final Height (Ht) SDS < -2] occurred in 25% of patients with no difference between the two groups of patients. Insulin growth factor 1 (IGF-1) SDS was low in 35.7 % of patients with no statistical difference among the two groups. Impaired fasting blood glucose occurred in 17.8% of patients, diabetes mellitus in 25% and hypogonadotropic hypogonadism in 10.7% of them. Morning cortisol was low in one patient. No thyroid or hypo-parathyroid abnormalities were detected in any patient. Liver iron content (LIC) > 15 mg/g dry weight and SF > 2,000 ng/mL were detected in 75% of the patients. The values resulted significantly higher in the transfused group (Group 2). High liver enzyme level (ALT) was detected in 42.8 % of patients, and the values were significantly higher in the transfused group (Group 2). Total and fetal Hb was significantly higher in group 1 versus group 2. Osteopenia was diagnosed in 14.3% of patients. Females had significantly better final height SDS, higher IGF-1 SDS, lower LIC and fasting blood glucose level compared to males. Significant correlations were found between Ht-SDS and IGF-1 SDS; LIC and SF, level; ALT and LIC, SF levels. Total and fetal Hb did not correlate significantly with Ht-SDS or IGF-1 level.

CONCLUSIONS

A significant number of TI patients have high LIC, short stature and endocrine disorders. Patients who require occasional transfusions have more liver iron overload and higher hepatic dysfunction. Females appear to attain a better final adult height and have higher IGF1-SDS versus males. Our data emphasize the need for long term surveillance for identification of organ-specific risk factors and early disease manifestations. We also recommend close monitoring of endocrine and other complications, according to the international guidelines.

A Perception on Genome-Wide Genetic Analysis of Metabolic Traits in Arab Populations

Despite dedicated nation-wide efforts to raise awareness against the harmful effects of fast-food consumption and sedentary lifestyle, the Arab population continues to struggle with an increased risk for metabolic disorders. Unlike the European population, the Arab population lacks well-established genetic risk determinants for metabolic disorders, and the transferability of established risk loci to this population has not been satisfactorily demonstrated. The most recent findings have identified over 240 genetic risk loci (with ~400 independent association signals) for type 2 diabetes, but thus far only 25 risk loci (ADAMTS9, ALX4, BCL11A, CDKAL1, CDKN2A/B, COL8A1, DUSP9, FTO, GCK, GNPDA2, HMG20A, HNF1A, HNF1B, HNF4A, IGF2BP2, JAZF1, KCNJ11, KCNQ1, MC4R, PPARγ, SLC30A8, TCF7L2, TFAP2B, TP53INP1, and WFS1) have been replicated in Arab populations. To our knowledge, large-scale population- or family-based association studies are non-existent in this region. Recently, we conducted genome-wide association studies on Arab individuals from Kuwait to delineate the genetic determinants for quantitative traits associated with anthropometry, lipid profile, insulin resistance, and blood pressure levels. Although these studies led to the identification of novel recessive variants, they failed to reproduce the established loci. However, they provided insights into the genetic architecture of the population, the applicability of genetic models based on recessive mode of inheritance, the presence of genetic signatures of inbreeding due to the practice of consanguinity, and the pleiotropic effects of rare disorders on complex metabolic disorders. This perspective presents analysis strategies and study designs for identifying genetic risk variants associated with diabetes and related traits in Arab populations.

Endocrine Complications

More than five decades ago, thalassemia major (TM) was fatal in the first decade of life [...]

Final adult height and endocrine complications in young adults with β-thalassemia major (TM) who received oral iron chelation (OIC) in comparison with those who did not use OIC

BACKGROUND

Relatively little is known about endocrine function, bone mineral health, and growth during oral iron chelation therapy in β-thalassemia major patients (TM) on treatment with deferasirox.

AIMS OF THE STUDY

To study the frequency of endocrine complications, IGF-1 levels and final adult standing height (FA-Ht) in patients with BTM in two groups of adult patients.

PATIENTS AND METHODS

The first group (Group A; 15 patients, 6 females and 9 males) received oral iron chelation therapy (OIC) with deferasirox for 6 years before puberty; the second group (Group B;40 patients) attained the FA-Ht before the use of OIC (iron chelation therapy with deferoxamine (DFO) given subcutaneously, since the age of 2 years). In both groups liver iron concentration was measured using FerriScan ® R2-MRI method. Furthermore, the FA-Ht, bode mass index (BMI), and insulin growth factor-1 (IGF-1) in a selected group of adult patients [9 with normal growth hormone (GH) secretion (GHN) and 8 with GH deficiency (GHD; peak GH response to provocative test  with clonidine: < 7 ng/ml), who were on iron chelation therapy with DFO given subcutaneously that was changed to oral deferasirox during the last 5-6 years. These 15 patients were not treated with rhGH.

RESULTS

Adults with BTM who received OIC for 6 years or more before attaining their FA-Ht, had lower liver iron concentration (LIC) assessed by FerriScan® R2-MRI, fasting glucose level (FBG) and liver enzymes (ALT and AST), and a better FA-Ht expressed in standard deviation score (FA-Ht-SDS), and higher IGF-1 SDS versus those who did not receive OIC before attaining FA-Ht. The prevalence of endocrinopathies, including hypothyroidism and hypogonadism were significantly lower in Group A versus Group B.  Comparison between the group with normal GHN and those with GHD showed that the FA-Ht-SDS of those with GHD (159.1± 6.42 cm). Ht-SDS = -2.5 ± 0.9) was significantly decreased compared to the group with NGH (Ht = 163.5 ± 5.2 cm, Ht-SDS = -1.74 ± 0.83).  The IGF-1-SDS did not differ between the two groups. Neither ferritin level nor IGF-1 concentrations were correlated with the Ht-SDS. The final FA-Ht-SDS correlated significantly with the peak GH secretion (r = 0.788, p = 0.0008). The FA-Ht-SDS were positively related to their mid-parental height (r=0.58, P <0.01).

CONCLUSIONS

The use of OIC years before the end of puberty was associated with a significantly lower prevalence of endocrinopathies, improvement of LIC and FA-Ht. The final adult height of patients with BTM and GHD was significantly shorter compared to their pears with NGH. rhGH therapy can be recommended for the treatment of thalassemic children and adolescents with GHD in addition to proper blood transfusion and intensive chelation to improve their final height.

Growth hormone therapy for people with thalassaemia

BACKGROUND

Thalassaemia is a recessively-inherited blood disorder that leads to anaemia of varying severity. In those affected by the more severe forms, regular blood transfusions are required which may lead to iron overload. Accumulated iron from blood transfusions may be deposited in vital organs including the heart, liver and endocrine organs such as the pituitary glands which can affect growth hormone production. Growth hormone deficiency is one of the factors that can lead to short stature, a common complication in people with thalassaemia. Growth hormone replacement therapy has been used in children with thalassaemia who have short stature and growth hormone deficiency.

OBJECTIVES

To assess the benefits and safety of growth hormone therapy in people with thalassaemia.

SEARCH METHODS

We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles, reviews and clinical trial registries. Our database and trial registry searches are current to 10 August 2017 and 08 August 2017, respectively.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing the use of growth hormone therapy to placebo or standard care in people with thalassaemia of any type or severity.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion. Data extraction and assessment of risk of bias were also conducted independently by two authors. The quality of the evidence was assessed using GRADE criteria.

MAIN RESULTS

One parallel trial conducted in Turkey was included. The trial recruited 20 children with homozygous beta thalassaemia who had short stature; 10 children received growth hormone therapy administered subcutaneously on a daily basis at a dose of 0.7 IU/kg per week and 10 children received standard care. The overall risk of bias in this trial was low except for the selection criteria and attrition bias which were unclear. The quality of the evidence for all major outcomes was moderate, the main concern was imprecision of the estimates due to the small sample size leading to wide confidence intervals. Final height (cm) (the review's pre-specified primary outcome) and change in height were not assessed in the included trial. The trial reported no clear difference between groups in height standard deviation (SD) score after one year, mean difference (MD) -0.09 (95% confidence interval (CI) -0.33 to 0.15 (moderate quality evidence). However, modest improvements appeared to be observed in the following key outcomes in children receiving growth hormone therapy compared to control (moderate quality evidence): change between baseline and final visit in height SD score, MD 0.26 (95% CI 0.13 to 0.39); height velocity, MD 2.28 cm/year (95% CI 1.76 to 2.80); height velocity SD score, MD 3.31 (95% CI 2.43 to 4.19); and change in height velocity SD score between baseline and final visit, MD 3.41 (95% CI 2.45 to 4.37). No adverse effects of treatment were reported in either group; however, while there was no clear difference between groups in the oral glucose tolerance test at one year, fasting blood glucose was significantly higher in the growth hormone therapy group compared to control, although both results were still within the normal range, MD 6.67 mg/dL (95% CI 2.66 to 10.68). There were no data beyond the one-year trial period.

AUTHORS' CONCLUSIONS

A small single trial contributed evidence of moderate quality that the use of growth hormone for a year may improve height velocity of children with thalassaemia although height SD score in the treatment group was similar to the control group. There are no randomised controlled trials in adults or trials that address the use of growth hormone therapy over a longer period and assess its effect on final height and quality of life. The optimal dosage of growth hormone and the ideal time to start this therapy remain uncertain. Large well-designed randomised controlled trials over a longer period with sufficient duration of follow up are needed.

Does Insulin Like Growth Factor-1 (IGF-1) Deficiency Have a "Protective" Role in the Development of Diabetic Retinopathy in Thalassamia Major Patients?

RATIONALE

Both insulin and IGF-1 have been implicated in the control of retinal endothelial cell growth, neovascularization and diabetic retinopathy. Recent findings have established an essential role for IGF-1 in angiogenesis and demonstrated a new target for control of retinopathy that explains why diabetic retinopathy initially increases with the onset of insulin treatment.

OBJECTIVE

This cross-sectional study was designed to give insights into relationship between Insulin-Growth-Factor 1 (IGF-1) levels and diabetic retinopathy (DR) in a sample of thalassemia major (TM) patients with insulin dependent diabetes mellitus (IDDM). This relation was not previously evaluated, despite the fact that both diseases co-exist in the same patient. The study also describes the clinical and biochemical profile of the associated complications in TM patients with and without IDDM.

DESIGN

A population-based cross-sectional study.

PARTICIPANTS

The study includes 19 consecutive TM patients with IDDM and 31 age- and sex-matched TM patients without IDDM who visited our out-patient clinics for an endocrine assessment.

METHODS

An extensive medical history, with data on associated complications and current medications, was obtained. Blood samples were drawn in the morning after an overnight fast to measure the serum concentrations of IGF-1, glucose, fructosamine, free thyroxine (FT4), thyrotropin (TSH) and biochemical analysis. Serologic screening assays for hepatitis C virus seropositivity (HCVab and HCV-RNA) were also evaluated; applying routine laboratory methods. Plasma total IGF-1 was measured by a chemiluminescent immunometric assay (CLIA) method. Ophthalmology evaluation was done by the same researcher using stereoscopic fundus biomicroscopy through dilated pupils. DR was graded using the scale developed by the Global Diabetic Retinopathy Group. Iron stores were assessed by direct and indirect methods.

RESULTS

Eighteen TM patients with IDDM (94.7 %) and ten non-diabetic patients (32.2 %) had IGF-1 levels below the 2.5(th) percentile of the normal values for the Italian population. The mean serum IGF-1 concentrations were significantly lower in the diabetic versus the non-diabetic TM groups (p < 0.001). DR was present in 4 (21 %) of 19 TM patients with IDDM and was associated with the main classical risk factors, namely inefficient glycemic control and duration of the disease but not hypertension. Using the scale developed by the Global Diabetic Retinopathy Group, the DR in our patients was classified as non proliferative diabetic retinopathy (NPDR). Only a few numbers of microaneurysms [1-3] were detected. Our data also confirm the strong association of IDDM in TM patients with other endocrine and non-endocrine complications.