Retesting the childhood-onset GH-deficient patient

Transient Isolated, Idiopathic Growth Hormone Deficiency-A Self-Limiting Pediatric Disease with Male Predominance or a Diagnosis Based on Uncertain Criteria? Lesson from 20 Years' Real-World Experience with Retesting at One Center

In the majority of children with growth hormone (GH) deficiency (GHD), normal GH secretion may occur before the attainment of final height. The aim of the study was to assess the incidence of persistent and transient GHD and the effectiveness of recombined human GH (rhGH) therapy in children with isolated, idiopathic GHD with respect to the moment of therapy withdrawal and according to different diagnostic criteria of GHD. The analysis included 260 patients (173 boys, 87 girls) with isolated, idiopathic GHD who had completed rhGH therapy and who had been reassessed for GH and IGF-1 secretion. The incidence of transient GHD with respect to different pre- and post-treatment criteria was compared together with the assessment of GH therapy effectiveness. The incidence of transient GHD, even with respect to pediatric criteria, was very high. Normal GH secretion occurred before the attainment of near-final height. Application of more restricted criteria decreased the number of children diagnosed with GHD but not the incidence of transient GHD among them. Poor response to GH therapy was observed mainly in the patients with normal IGF-1 before treatment, suggesting that their diagnosis of GHD may have been a false positive. Further efforts should be made to avoid the overdiagnosis GHD and the overtreatment of patients.

Approach to the Patient: Management of Pituitary Hormone Replacement Through Transition

Hypopituitarism in childhood is a rare, complex disorder that can present with highly variable phenotypes, which may continue into adult life. Pituitary deficits can evolve over time, with unpredictable patterns resulting in significant morbidity and mortality. Hypopituitarism and hypothalamic dysfunction may be associated with challenging comorbidities such as obesity, learning difficulties, behavioral issues, sleep disturbance, and visual impairment. Transition is the purposeful planned movement of adolescents and young adults with chronic conditions from child-centered to adult-oriented health care systems with a shift from parent- to patient-focused care. To achieve effective transition within a health care setting, the inherent challenges involved in the evolution from a dependent child to an independent adult must be recognized. Transition is a critical time medically for patients with hypopituitarism. Complex issues with respect to puberty, attainment of optimal stature, adherence to treatment, and acceptance of the need for life-sustaining medications need to be addressed. For health care professionals, transition is an opportunity for reassessment of the pituitary deficits and the need for lifelong replacement therapies, often against a background of complex psychological issues. We present 4 illustrative cases of hypopituitarism of differing etiologies with diverse clinical presentations. Diagnostic and management processes from clinical presentation to young adulthood are discussed, with a particular focus on needs and outcomes through transition.

Prevalence of growth hormone (GH) deficiency in previously GH-treated young adults with Prader-Willi syndrome

OBJECTIVE

Some features of subjects with Prader-Willi syndrome (PWS) resemble those seen in growth hormone deficiency (GHD). Children with PWS are treated with growth hormone (GH), which has substantially changed their phenotype. Currently, young adults with PWS must discontinue GH after attainment of adult height when they do not fulfil the criteria of adult GHD. Limited information is available about the prevalence of GHD in adults with PWS. This study aimed to investigate the GH/insulin-like growth factor (IGF-I) axis and the prevalence of GHD in previously GH-treated young adults with PWS.

DESIGN

Cross-sectional study in 60 young adults with PWS.

MEASUREMENTS

Serum IGF-I and IGFBP-3 levels, GH peak during combined growth hormone-releasing hormone (GHRH)-arginine stimulation test.

RESULTS

Serum IGF-I was <-2 standard deviation scores (SDS) in 2 (3%) patients, and IGFBP-3 was within the normal range in all but one patient. Median (IQR) GH peak was 17.8 μg/L (12.2; 29.7) [~53.4 mU/L] and below 9 μg/L in 9 (15%) patients. Not one patient fulfilled the criteria for adult GHD (GH peak < 9 μg/L and IGF-I < -2 SDS), also when BMI-dependent criteria were used. A higher BMI and a higher fat mass percentage were significantly associated with a lower GH peak. There was no significant difference in GH peak between patients with a deletion or a maternal uniparental disomy (mUPD).

CONCLUSIONS

In a large group of previously GH-treated young adults with PWS, approximately 1 in 7 exhibited a GH peak <9 μg/L during a GHRH-arginine test. However, none of the patients fulfilled the consensus criteria for adult GHD.

Childhood-onset growth hormone deficiency and the transition to adulthood: current perspective

Childhood-onset growth hormone deficiency (CO-GHD) is an endocrine condition associated with a broad range of health issues from childhood through to adulthood, which requires particular attention during the transition period from adolescence to young adulthood. There is uncertainty in the clinical practice of the management of CO-GHD during transition regarding the clinical assessment and management of individual patients during and after transition to obtain optimal follow-up and improved health outcomes. Despite the availability of clinical guidelines providing the framework for transition of young adults with CO-GHD, there remains substantial variation in approaching transitional care among pediatric and adult services. A well-structured and coordinated transitional plan with clear communication and direct collaboration between pediatric and adult health care to ensure optimal management of adolescents with CO-GHD during transition is needed.

New Neoplasm During GH Replacement in Adults With Pituitary Deficiency Following Malignancy: A KIMS Analysis

CONTEXT

Data on the association between growth hormone (GH) replacement in patients with GH deficiency (GHD) after malignancies and new neoplasms show conflicting results.

OBJECTIVE

To clarify the incidence of new malignant neoplasm in childhood-onset (CO) and adult-onset (AO) adult cancer survivors (CSs).

DESIGN

Retrospective comparison of CO-CS and AO-CS with CO idiopathic GHD (IGHD) and AO nonfunctioning pituitary adenoma (NFPA) patients and with the general population [standardized incidence ratio (SIR)].

SETTING

Data from the Pfizer International Metabolic Database study (KIMS).

PATIENTS

CO-CS [n = 349; 50.4% females; mean baseline (MBL) IGF-I standard deviation score (SDS), -2.4], IGHD (n = 619; 35.7% females; MBL IGF-I SDS, -3.4), AO-CS (n = 174; 42.5% females; MBL IGF-I SDS, -1.4), and NFPA (n = 2449; 38.1% females; MBL IGF-I SDS, -1.0).

MAIN OUTCOME MEASURES

SIRs of malignant neoplasms.

RESULTS

After a median follow-up of 5.9 years (2192 patient-years), 15 CO-CS (4.3%) had developed 16 new neoplasms. The SIR was 10.4 [95% confidence interval (CI), 5.9 to 16.9] and 6.5 (95% CI, 3.0 to 12.4) after exclusion of seven patients with skin cancers. In IGHD, three malignant neoplasms (0.5%) were observed after a median follow-up of 5.4 years (3908 patient-years; SIR, 0.47; 95% CI, 0.09 to 1.37). New malignant neoplasms occurred in three AO-CS (1.7%; SIR, 1.1; 95% CI, 0.2 to 3.2) and 146 NFPA patients (153 cases, 6.0%; SIR, 1.1; 95% CI, 0.9 to 1.2) after a median follow-up of 4.9 (1024 patient-years) and 5.6 years (15,215 patient-years).

CONCLUSIONS

The risk of second malignant neoplasms was increased in CO-CS but not in AO-CS, which illustrates the need to closely follow patients on GH replacement because of a prior malignancy.

Growth hormone treatment of adolescents with growth hormone deficiency (GHD) during the transition period: results of a survey among adult and paediatric endocrinologists from Italy. Endorsed by SIEDP/ISPED, AME, SIE, SIMA

Treatment of adolescents with growth hormone deficiency (GHD) during the transition period is a controversial issue. This paper is a contribution from the Italian community of paediatric and adult endocrinologists surveyed in a Delphi panel. The Delphi method is a structured communication technique, originally developed as a systematic, interactive forecasting method that relies on a panel of experts. The experts answer questionnaires in two or more rounds. There was substantial agreement on the definition of the problems associated with the diagnosis and treatment of adolescents with GHD in the transition period, as well as on the identification of the controversial issues which need further studies. There is general consensus on the need of re-testing all isolated idiopathic GHD after at least 30-day withdrawn from treatment, while in patients with multiple pituitary deficiency and low IGF-I levels there is generally no need to re-test. In patients with permanent or confirmed GHD, a starting low rhGH dose (0.01-0.03 mg per day) to be adjusted according to IGF-I concentrations is also widely accepted. For those continuing treatment, the optimal therapeutic schedule to obtain full somatic maturation, normalization of body composition and bone density, cardiovascular function and Quality of Life, need to be evaluated.

Growth Hormone Deficiency and Lysinuric Protein Intolerance: Case Report and Review of the Literature

BACKGROUND

Lysinuric protein intolerance (LPI; MIM# 222700) is a rare metabolic disorder caused by a defective cationic amino acids (CAA) membrane transport leading to decreased circulating plasma CAA levels and resulting in dysfunction of the urea cycle. Short stature is commonly observed in children with LPI and has been associated with protein malnutrition. A correlation between LPI and growth hormone deficiency (GHD) has also been postulated because of the known interaction between the AA arginine, ornithine, and lysine and growth hormone (GH) secretion. Our report describes a case of GHD in an LPI patient, who has not presented a significant increase in growth velocity with recombinant-human GH (rhGH) therapy, suggesting some possible pathogenic mechanisms of growth failure.

CASE PRESENTATION

The proband was a 6-year-old boy, diagnosed as suffering from LPI, erythrophagocytosis (HP) in bone marrow, and short stature. Two GH provocative tests revealed GHD. The patient started rhGH therapy and a controlled-protein diet initially with supplementation of oral arginine and then of citrulline. At 3-year follow-up, no significant increase in growth velocity and in insulin-like growth factor-1 (IGF-1) levels was observed. Inadequate nutrition and low plasmatic levels of arginine, ornithine, lysine, and HP may have contributed to his poor growth.

CONCLUSION

Our case suggests that growth failure in patients with GHD and LPI treated with rhGH could have a complex and multifactorial pathogenesis. Persistently low plasmatic levels of lysine, arginine, and ornithine, associated with dietary protein and caloric restriction and systemic inflammation, could determine a defect in coupling GH to IGF-1 production explaining why GH replacement therapy is not able to significantly improve growth impairment. We hypothesize that a better understanding of growth failure pathophysiology in these patients could lead to the development of more rational strategies to treat short stature in patients with LPI.

IGF-I bioactivity might reflect different aspects of quality of life than total IGF-I in GH-deficient patients during GH treatment

CONTEXT

No relationship has been found between improvement in quality of life (QOL) and total IGF-I during GH therapy.

AIM

Our aim was to investigate the relationship between IGF-I bioactivity and QOL in GH-deficient (GHD) patients receiving GH for 12 months.

METHODS

Of 106 GHD patients, 84 on GH treatment discontinued therapy 4 weeks before establishing baseline values and 22 were GH-naive. IGF-I bioactivity was determined by IGF-I kinase receptor activation assay, total IGF-I by immunoassay (Immulite), and QOL by the disease-specific Question on Life Satisfaction Hypopituitarism (QLS-H) module and by the general SF-36 questionnaire (SF-36Q).

RESULTS

IGF-I bioactivity increased after 6 months (-2.5 vs -1.9 SD, P < .001) and did not further increase after 12 months (-1.8 SD, P = .23); total IGF-I increased from -2.3 to -0.9 SD (P < .001) and to -0.6 SD (P = .005), respectively. QLS-H did not change over 12 months (-0.66 ± 0.16 to -0.56 ± 0.17 SD [P = .42] to -0.68 ± 0.17 SD [P = .22]). The mental component summary of the SF-36Q increased from 47.4 (38.7-52.8) to 50.2 (43.1-55.3) (P = .001) and did not further improve (49.4 [42.1-54.1], P = .19); the physical component summary did not change (47.5 [42.0-54.2] vs 47.0 [41.9-55.3], P = .91, vs 48.3 [39.9-55.4], P = .66). After 12 months, IGF-I bioactivity was related to QLS-H (r = 0.28, P = .01); total IGF-I was not (r = 0.10, P = .37). IGF-I bioactivity and total IGF-I were related to PCS (r = 0.35, P = .001; and r = 0.31, P = .003).

CONCLUSION

IGF-I bioactivity remained subnormal after GH treatment and was positively related to QLS-H, whereas total IGF-I was not. This suggests that IGF-I bioactivity reflects different aspects of QOL than total IGF-I in GHD patients during GH treatment.

The Challenge of Growth Hormone Deficiency Diagnosis and Treatment during the Transition from Puberty into Adulthood

In children with childhood-onset growth hormone deficiency, replacement GH therapy is effective in normalizing height during childhood and achieving adult height within the genetic target range. GH has further beneficial effects on body composition and metabolism through adult life. The transition phase, defined as the period from mid to late teens until 6-7 years after the achievement of final height, represents a crucial time for reassessing children's GH secretion and deciding whether GH therapy should be continued throughout life. Evidence-based guidelines for diagnosis and treatment of growth hormone deficient children during transition are lacking. The aim of this review is to critically review the up-to-date evidence on the best management of transition patients in order to ensure the correct definitive diagnosis and establish the appropriate therapeutic regimen.

A review of guidelines for use of growth hormone in pediatric and transition patients

Growth hormone (GH) is approved by the US Food and Drug Administration (FDA) for use in pediatric patients with disorders of growth failure or short stature and in adults with growth hormone deficiency (GHD) and HIV/AIDS wasting and cachexia. For pediatric patients, guidelines for the use of GH have been developed by several organizations that have identified specific criteria for initiating GH therapy for each FDA-approved indication. Guidelines for adults have also been developed and include recommendations for transition (adolescent) patients with GHD. These patients are often treated with GH as children but may require continued treatment as young adults to attain full skeletal mineralization and improve cardiovascular risk factors. Adult and pediatric guidelines are supported by efficacy and safety studies, which show that, when started at an early age, GH treatment can increase growth velocity and that GH is safe and well-tolerated. We summarize the guidelines that are available for all FDA-approved indications among pediatric and transition patients. Adherence to these guidelines will help to ensure that patients with disorders of growth failure or short stature receive the necessary therapy to increase linear growth and transition smoothly to healthy adulthood.

Growth hormone deficiency in the transition period: body composition and gonad function

Recombinant GH therapy is normally administered to GH-deficient children in order to achieve a satisfactory height - the main target during childhood and adolescence. However, the role of GH does not end once final height has been reached, but continues during the so-called transition period. In this phase of life, the body undergoes several changes, both physical and psychological, that culminate in adulthood. During this period, GH has a part in numerous metabolic functions. These include the lipid profile, where it increases HDL and reduces LDL, with the global effect of cardiovascular protection. It also has important effects on body composition (improved muscle strength and lean body mass and reduced body fat), the achievement of proper peak bone density, and gonad maturation. Retesting during the transition period, involving measurement of IGF-I plus a provocative test (insulin tolerance test or GHRH + arginine test), is thus necessary to establish any persistent GH deficiency requiring additional replacement therapy. The close cooperation of the medical professionals involved in the patient's transition from a pediatric to an adult endocrinologist is essential. The aim of this review is to point out the main aspects of GH treatment on body composition, metabolic and gonad functions in the transition period.

Early changes in body composition after cessation of growth hormone therapy in childhood-onset growth hormone deficiency

At final height, somatic maturity has not been reached yet. We investigated bone and body composition in patients, who completed pediatric growth hormone (GH) treatment at final height. After a mean period of 0.55 ± 0.17 yr off GH treatment 90 (66 m/24 f) childhood-onset growth hormone deficiency (GHD) patients were reinvestigated for GHD by insulin tolerance testing at a mean age of 17.52 ± 1.50 yr. Thirty-seven (25 m/12 f) patients remained GH deficient (persistent GHD). Bone and body composition were measured using peripheral quantitative computed tomography of the nondominant forearm. Bone mineral density (BMD) was within normal limits. Total cross-sectional bone area Z-score (0.64 ± 1.3) was significantly higher as a result of an enlarged medullary cavity Z-score (1.12 ± 1.2) leading to reduction of cortical thickness Z-score (-1.21 ± 1.0). Patients with persistent GHD had a significantly higher fat mass (13.3 ± 8.7 and 6.8 ± 4.6 cm(2), p<0.05), which was more pronounced in multiple pituitary hormone deficiency patients. Shortly after cessation of GH treatment in patients treated for childhood-onset GHD age adequate normal BMD and enlarged diaphysis was detectable. Patients with persistent GHD status had a significant higher fat mass.

The diagnosis and treatment of growth hormone deficiency in adults

PURPOSE OF REVIEW

This review summarizes the recent published information regarding efficacy and complications of growth hormone replacement therapy. Several recent reports have monitored patients for periods of up to 10 years. Additionally, a consensus conference has been held regarding needed improvements in diagnostic testing and the recommendations of consensus panels regarding diagnostic criteria and laboratory test utilization are summarized.

RECENT FINDINGS

Long-term studies show growth hormone can be administered safely and that muscle strength and function as well as lipoprotein abnormalities and low-bone mineral density show sustained improvement over extended periods of time. The complications that occur are generally dose-dependent and once attenuated do not tend to recur. Long-term safety studies regarding improvement in cardiovascular mortality and/or worsening prognosis for patients who develop malignancies are available only in the form of observational studies and randomized controlled long-term trial information is not yet available. The studies reported provide a means for clinicians to ascertain the patients who are likely to derive the greatest benefit from growth hormone when the appropriate diagnostic testing and treatment paradigms are utilized.

SUMMARY

The studies that are summarized provide useful information for assessing the response to treatment, selecting patients who are candidates for long-term replacement therapy and for selecting those in whom the need for therapy may need to be reassessed.

Growth hormone deficiency: diagnosis and therapy in children

Growth hormone (GH) deficiency (GHD) represents a condition characterized by reduced GH secretion, isolated or associated with other pituitary hormone deficiencies. Diagnosis of GHD in childhood is achieved by secretagogs testing in combination with auxological parameters, such as height and growth velocity and biochemical and radiological findings. Only after excluding other causes of growth failure should a careful assessment of the pituitary-IGF-1 axis be undertaken, using GH-provocative tests and basal serum IGF-I values. As recommended by the GH Research Society, patients with GHD should be treated with recombinant human GH in order to normalize height during childhood and, ultimately, attain a normal adult height.

A reappraisal of diagnosing GH deficiency in adults: role of gender, age, waist circumference, and body mass index

OBJECTIVE

The objective of the study was to reevaluate the diagnostic accuracy of GH peak after GHRH plus arginine test (GHRH+ARG) according to patients' age, body mass index (BMI), and waist circumference to diagnose GH deficiency (GHD).

OUTCOME MEASURES

GH peak after GHRH+ARG and IGF-I levels reported as sd score.

SUBJECTS

Subjects included 408 controls (218 women, 190 men, aged 15-80 yr) and 374 patients with hypopituitarism (167 women, 207 men, aged 16-83 yr).

RESULTS

In the (elderly) healthy subjects 15-25 yr old (young), 26-65 yr old (adults) and older than 65 yr, GH cutoffs were 15.6, 11.7, and 8.5 microg/liter, 11.8, 8.1, and 5.5 microg/liter, and 9.2, 6.1, and 4.0 microg/liter, respectively, in the lean, overweight, and obese subjects. Waist circumference was the best predictor of GH peak (t = -7.6, P < 0.0001) followed by BMI (t = -6.7, P < 0.0001) and age (t = -5.7, P < 0.0001). Based on the old (<9.1 microg/liter) and new GH cutoff, 286 (76.5%) and 276 (73.8%) of 374 hypopituitary patients had severe GHD. The receiving-operator characteristic analysis showed GH cutoffs in line with the third percentile or slightly higher results so that the prevalence of GHD increased to 90.1%.

CONCLUSIONS

The results of the current study show that waist circumference and BMI are the strongest predictors of GH peak after GHRH+ARG followed by age. However, the old cutoff value of 9.0 microg/liter was in line with the new cutoffs in 95% of patients.