Growth hormone secretion in polytransfused prepubertal patients with homozygous beta-thalassemia. Effect of long-term recombinant GH (recGH) therapy

A Systematic Review and Meta-Analysis of Stature Growth Complications in β-thalassemia Major Patients

Background

Blood transfusion is a traditional treatment for β-thalassemia (β-thal) that improves the patients' anemia and lifespan, but it may lead to iron overload in parenchymal tissue organs and endocrine glands that cause their dysfunctions as the iron regulatory system can't excrete excess iron from the bloodstream.

Objective

To evaluate the prevalence of iron-related complications (short stature, growth retardation, and growth hormone deficiency) in β-thalassemia major (βTM) patients.

Methods

We performed an electronic search in PubMed, Scopus, and Web of Sciences to evaluate the prevalence of growth hormone impairment in β-thalassemia major (βTM) patients worldwide. Qualities of eligible studies were assessed by the Joanna Briggs Institute checklist for the prevalence study. We used Comprehensive Meta-Analysis (Version 2) to calculate the event rate with 95% CIs, using a random-effects model for all analyses.

Findings

Seventy-four studies were included from five continents between 1978 and 2019; 70.27% (Asia), 16.21% (Europe), 6.75% (Africa), 2.70% (America), 1.35% (Oceania), and 2.70% (Multicenter). The overall mean age of the participants was about 14 years. The pooled prevalence of short stature (ST) was 48.9% (95% CI 35.3-62.6) and in male was higher than female (61.9%, 95% CI 53.4-69.7 vs. 50.9%, CI 41.8-59.9). The pooled prevalence of growth retardation (GR) was 41.1% and in male was higher than in female (51.6%, 95% CI 17.8-84 vs. 33.1%, CI 9.4-70.2). The pooled prevalence of growth hormone deficiency (GHD) was 26.6% (95% CI 16-40.8).

Conclusion

Our study revealed that near half of thalassemia patients suffer from growth impairments. However, regular evaluation of serum ferritin levels, close monitoring in a proper institute, suitable and acceptable treatment methods besides regular chelation therapy could significantly reduce the patients' complications.

Growth and growth hormone treatment in children with chronic diseases

Growth hormone has been available for treatment of various conditions for over 50 years. There have been a number of chronic disease states in which it has been used, such as chronic kidney disease, which became a US Food and Drug Administration (FDA)-approved indication in 1993. For other chronic disease states there have been clinical studies supporting its use, but they have not yet been approved as a indications by the FDA. Examples of such diseases are cystic fibrosis, chronic arthritis, short bowel syndrome, burn trauma, and hypophosphatemic rickets.

Growth and endocrine function in thalassemia major in childhood and adolescence

BACKGROUND

Thalassemia major is an inherited hemoglobin disorder characterized by chronic anemia and iron overload due to transfusion therapy and gastrointestinal absorption. Iron overload causes most of the associated mortality and morbidity and frequently involves the endocrine glands.

AIM

To review the most pertinent literature on the topic.

METHODS

One hundred and twenty-three papers were evaluated.

RESULTS

Disproportionate short stature is frequent and becomes more evident at puberty because of the lack of growth spurt. Later on, partial height recovery may occur. Long-term treatment with recombinant human GH seems ineffective to improve final height. Pubertal development is characterized by a clinical spectrum ranging from hypogonadism to a simple delay in starting and developing of puberty. Hormonal replacement is mandatory in cases of absent or arrested puberty. Pancreatic beta-cells function may be impaired during adolescence or later on. Its impairment ranges from hyperinsulinemia, secondary to insulin resistance, with normal glucose tolerance to beta-cells failure with insulin-dependent diabetes mellitus. Primary hypothyroidism may affect thalassemic patients from the second decade of life. The thyroid dysfunction may be reversible (if an intensive chelation therapy regimen is started in the precocious phase), stationary, or slowly progressive. Central hypothyroidism is less common and autoimmune thyroiditis absent.

CONCLUSION

Despite the improvement of the treatment, the involvement of the endocrine system still burdens the life of these patients. Further therapeutic improvement would reasonably reduce morbidity and, hopefully, mortality of thalassemic patients and make the endocrine disorders easier to treat.

Thalassaemia and aberrations of growth and puberty

Endocrine dysfunction in Thalassaemia major (TM) is a common and disturbing complication, which requires prompt recognition and treatment. The contribution of the underlying molecular defect in TM to the development of endocrinopathies is significant because the patients with the more severe genetic defects have a greater rate of iron loading through higher red cell consumption. TM patients frequently present delay of growth and puberty with reduction of final height. The pathogenesis of growth failure is multifactorial and is mainly due to chronic anemia and hypoxia, chronic liver disease, zinc and folic acid deficiency, iron overload, intensive use of chelating agents, emotional factors, and endocrinopathies (hypogonadism, delayed puberty, hypothyroidism) and GH-IGF-1 axis dysregulation. Although appropriate iron chelation therapy can improve growth and development, TM children and adolescents treated intensively with desferrioxamine remain short as well, showing body disproportion between the upper and lower body segment. Body disproportion is independent of pubertal or prepubertal period of greater height gain. Treatment with recombinant GH (rhGH) is recommended when GH deficiency is established, and even so, the therapeutic response is often non satisfactory. Growth acceleration is mostly promoted with sex steroids in children with associated pubertal delay. Sexual complications in TM, which include Delayed Puberty, Arrested Puberty and Hypogonadism, present the commonest endocrine complication. Iron deposition on gonadotroph cells of the pituitary leads to disruption of gonadotrophin production which is proven by the poor response of FSH and LH to GnRH stimulation. In the majority of patients gonadal function is normal as most women with Amenorrhea are capable of achieving pregnancy with hormonal treatment and similarly men with azoospermia become fathers. Secondary Hypogonadism appears later in life, and is manifested in women as Secondary Amenorrhea and in men as decline in sexual drive and azzoospermia. The damage to the hypothalamus and pituitary is progressive, even when intensive chelating therapy is given and the appearance of Hypogonadism in both sexes is often unavoidable. Close follow up and proper management is crucial for every patient with TM. Early recognition of growth disturbance and prevention of hypogonadism by early and judicious chelation therapy is mandatory for the improvement of their quality of life. Patients with TM can now live a better life due to modern advances in their medical care and our better understanding in the pathogenesis, manifestation and prevention of endocrine complications.

[Growth hormone therapy for children with chronic diseases]

Growth disorders are commonly observed in children suffering from chronic diseases. The pathogenesis of growth failure is multifactorial. In chronic inflammatory diseases such as juvenile idiopathic arthritis and inflammatory bowel disease, growth is also affected by pro-inflammatory cytokines. Patients with chronic diseases might also become growth hormone (GH) deficient. However, normal or increased GH secretion with reduced plasma concentrations of insulin-like growth factor-I indicate a degree of GH insensitivity in some patients. Growth damage can increase with specific treatments, especially if glucocorticoids are used. GH therapy has been used to reduce the consequences of the disease and long-term steroid therapy in these patients. In this review, it is reported the encouraging results of GH treatment in growth-retarded children with chronic diseases, both in well defined indications as well in situations still under investigation.

Growth hormone reserve in adult beta thalassemia patients

Reduced serum insulin-like growth factor-1 (IGF-1) and hypogonadotrophic hypogonadism are common features of adult beta-thalassemia, and warrant evaluation of the growth hormone (GH)-IGF-1 axis. The aim of this study was to determine GH reserve in beta-thalassemia patients (9 females, 7 males, 15 major, 1 intermedia), age 29.3 +/- 6.9 years, BMI 21.3 +/- 1.9 kg/m2, and in 20 age, sex and BMI-matched healthy controls, using the GH-releasing hormone (GHRH)-arginine test. The associations between peak GH response and hormonal and biochemical indices were evaluated. Using BMI-related cut-off limits for peak GH response in the GHRH-arginine test, 4/16 beta-thalassemia patients had peak GH lower than 11.5 microg/l, the cut-off limit suggested for lean subjects, and were diagnosed as GH deficient (GHD). Using 9 microg/l as the cut-off limit 2/16 patients were GHD. Reduced serum IGF-1 and IGFBP-3 were present in 69% and 19% of the patients, respectively. Peak GH did not correlate with serum IGF-1, TSH, and fT4 levels or gonadal status. Neither peak GH nor IGF-1 correlated with serum ferritin. Our findings suggest that GHD is present in up to a quarter of adult beta-thalassemia patients. The clinical benefits of GH therapy need to be determined. GHD alone does not account for the high prevalence of reduced IGF-1 in adult beta-thalassemia.

Final height in short polytransfused thalassemia major patients treated with recombinant growth hormone

We measured the final height (FH) of 25 short polytransfused thalassemia major (Th) patients (18 males) with a reduced GH reserve treated for 3.3 +/- 1.2 yr with recombinant GH (rhGH), 0.2 mg/kg/week sc. At baseline, all patients were clinically prepubertal; their chronological (CA) and bone ages (BA) were 13.6 +/- 2.0 and 11.4 +/- 1.6 yr, respectively. In 9 out of 18 males and 5 out of 7 females, the onset of puberty occurred spontaneously during the treatment. At the end of the rhGH administration, the height of the enrolled children was not significantly increased when calculated for CA (HxCA), while it was significantly decreased (p=0.004) when calculated for BA (HxBA); the BA increase (3.29 +/- 1.65 yr) was significantly higher (p<0.001) than the height age increase (2.16 +/- 0.98 yr). The FHxCA showed a significant increase (p=0.001) compared to both baseline and the end of therapy, while the FHxBA was significantly decreased (p<0.001) compared with the corresponding value at baseline. At the end of therapy, both HxCA and HxBA resulted positively related to the BA at baseline (r=0.50 and 0.42, p=0.012 and 0.034, respectively). FH was positively correlated with CA (r=0.63, p=0.001), BA (r=0.68, p<0.001) and HxBA (r=0.59, p=0.002) evaluated at baseline, and with both HxCA and HxBA (r=0.82 and 0.74, respectively, p<0.001), evaluated at the end of treatment. A negative correlation was found between FH and the length of treatment (r=-0.56, p=0.004). Our data seem to exclude that prolonged rhGH therapy could improve FH in Th patients; on the contrary, a negative effect may be hypothesized.