Confirmation of severe GH deficiency after final height in patients diagnosed as GH deficient during childhood

The landscape of retesting in childhood-onset idiopathic growth hormone deficiency and its reversibility: a systematic review and meta-analysis

OBJECTIVE

Children diagnosed with idiopathic isolated growth hormone deficiency (IGHD) are frequently observed to no longer be GH-deficient at a later stage of growth as a result of 'GHD reversal'. Reevaluation of GH status by stimulation test is currently incorporated into management guidelines at attainment of final height (FH). Over the past three decades, numerous studies have evaluated reversal rates using different methodologies including crucial parameters like GHD aetiology, GH cut-off and retesting time point, with heterogeneous results. We aimed to systematically analyse the reversibility of childhood-onset IGHD dependent on retesting GH cut-offs and retesting time points.

METHODS

PubMed, Cochrane Library, TRIP database and NHS Evidence were searched for publications investigating the reversibility of IGHD from database initiation to 30 June 2020 following PRISMA recommendations. Study cohorts were pooled according to retesting GH cut-off and time point. Reversal rates were calculated using random-effects models.

RESULTS

Of the 29 studies initially identified, 25 provided sufficient detail for IGHD analysis, resulting in 2030 IGHD patient data. Reversal rates decreased significantly as the retesting GH cut-off increased (P = 0.0013). Pooled (95% CI) reversal rates were 80% (59-92%, n = 227), 73% (62-81%, n = 516) and 55% (41-68%, n = 1287) for cohorts using retesting GH cut-offs of 3-4 ng/mL, 5-6 ng/mL and 7.7-10 ng/mL, respectively. Individuals retested at FH (n = 674) showed a pooled reversal rate of 74% (64-82%) compared to 48% (25-71%) when retested before FH (n = 653).

CONCLUSION

Provided evidence supports reevaluation of current IGHD management guidelines. The high reversal rates should instigate consideration of early retesting.

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.

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.

An audit of the management of childhood-onset growth hormone deficiency during young adulthood in Scotland

Background

Adolescents with childhood onset growth hormone deficiency (CO-GHD) require re-evaluation of their growth hormone (GH) axis on attainment of final height to determine eligibility for adult GH therapy (rhGH).

Aim

Retrospective multicentre review of management of young adults with CO-GHD in four paediatric centres in Scotland during transition.

Patients

Medical records of 130 eligible CO-GHD adolescents (78 males), who attained final height between 2005 and 2013 were reviewed. Median (range) age at initial diagnosis of CO-GHD was 10.7 years (0.1–16.4) with a stimulated GH peak of 2.3 μg/l (0.1–6.5). Median age at initiation of rhGH was 10.8 years (0.4–17.0).

Results

Of the 130 CO-GHD adolescents, 74/130(57 %) had GH axis re-evaluation by stimulation tests /IGF-1 measurements. Of those, 61/74 (82 %) remained GHD with 51/74 (69 %) restarting adult rhGH. Predictors of persistent GHD included an organic hypothalamic-pituitary disorder and multiple pituitary hormone deficiencies (MPHD). Of the remaining 56/130 (43 %) patients who were not re-tested, 34/56 (61 %) were transferred to adult services on rhGH without biochemical retesting and 32/34 of these had MPHD. The proportion of adults who were offered rhGH without biochemical re-testing in the four centres ranged between 10 and 50 % of their total cohort.

Conclusions

A substantial proportion of adults with CO-GHD remain GHD, particularly those with MPHD and most opt for treatment with rhGH. Despite clinical guidelines, there is significant variation in the management of CO-GHD in young adulthood across Scotland.

Reappraisal of serum insulin-like growth factor-I (IGF-1) measurement in the detection of isolated and combined growth hormone deficiency (GHD) during the transition period

OBJECTIVE

To evaluate the accuracy of serum IGF-1 in the detection of isolated (IGHD) or combined growth hormone deficiency (CGHD) at the transition phase.

SUBJECTS AND METHODS

Forty nine patients with GHD during childhood [16 with IGHD (10 men) and 33 with CGHD (24 men); age 23.2 ± 3.5 yrs.] were submitted to an insulin tolerance test (ITT) with a GH peak < 5 µg/L used for the diagnosis of GHD at the transition phase. Pituitary function and IGF-1 measurements were evaluated in the basal sample of the ITT. Transition patients were reclassified as GH-sufficient (SGH; n = 12), IGHD (n = 7), or CGHD (n = 30).

RESULTS

Five (31%) patients with IGHD and 32 (97%) with CGHD at childhood persisted with GHD at retesting. One patient with IGHD was reclassified as CGHD, whereas 3 patients with CGHD were reclassified as IGHD. Mean GH peak was 0.2 ± 0.3 µg/L in the CGHD, 1.3 ± 1.5 µg/L in the IGHD, and 18.1 ± 13.1 µg/L in the SGH group. Serum IGF-1 level was significantly higher in the SGH (272 ± 107 ng/mL) compared to IGHD (100.2 ± 110) and CGHD (48.7 ± 32.8) (p < 0.01). All patients reclassified as CGHD, 86% reclassified as IGHD, and 8.3% reclassified as SGH had low IGF-1 level, resulting in 97.3% sensitivity and 91.6% specificity in the detection of GHD at the transition period; the cutoff value of 110 ng/mL showed 94.5% sensitivity and 100% specificity. Mean IGF-1 values did not differ in IGHD or CGHD associated with one, two, three, or four additional pituitary deficiencies.

CONCLUSION

IGF-1 measurement is accurate to replace ITT as initial diagnostic test for IGHD and CGHD detection at the transition phase.

Isolated growth hormone deficiency (GHD) in childhood and adolescence: recent advances

The diagnosis of GH deficiency (GHD) in childhood is a multistep process involving clinical history, examination with detailed auxology, biochemical testing, and pituitary imaging, with an increasing contribution from genetics in patients with congenital GHD. Our increasing understanding of the factors involved in the development of somatotropes and the dynamic function of the somatotrope network may explain, at least in part, the development and progression of childhood GHD in different age groups. With respect to the genetic etiology of isolated GHD (IGHD), mutations in known genes such as those encoding GH (GH1), GHRH receptor (GHRHR), or transcription factors involved in pituitary development, are identified in a relatively small percentage of patients suggesting the involvement of other, yet unidentified, factors. Genome-wide association studies point toward an increasing number of genes involved in the control of growth, but their role in the etiology of IGHD remains unknown. Despite the many years of research in the area of GHD, there are still controversies on the etiology, diagnosis, and management of IGHD in children. Recent data suggest that childhood IGHD may have a wider impact on the health and neurodevelopment of children, but it is yet unknown to what extent treatment with recombinant human GH can reverse this effect. Finally, the safety of recombinant human GH is currently the subject of much debate and research, and it is clear that long-term controlled studies are needed to clarify the consequences of childhood IGHD and the long-term safety of its treatment.

Long-lasting effects of undernutrition

Undernutrition is one of the most important public health problems, affecting more than 900 million individuals around the World. It is responsible for the highest mortality rate in children and has long-lasting physiologic effects, including an increased susceptibility to fat accumulation mostly in the central region of the body, lower fat oxidation, lower resting and postprandial energy expenditure, insulin resistance in adulthood, hypertension, dyslipidaemia and a reduced capacity for manual work, among other impairments. Marked changes in the function of the autonomic nervous system have been described in undernourished experimental animals. Some of these effects seem to be epigenetic, passing on to the next generation. Undernutrition in children has been linked to poor mental development and school achievement as well as behavioural abnormalities. However, there is still a debate in the literature regarding whether some of these effects are permanent or reversible. Stunted children who had experienced catch-up growth had verbal vocabulary and quantitative test scores that did not differ from children who were not stunted. Children treated before 6 years of age in day-hospitals and who recovered in weight and height have normal body compositions, bone mineral densities and insulin production and sensitivity.

Multiple doses of pegylated long-acting growth hormone are well tolerated in healthy male volunteers and possess a potential once-weekly treatment profile

OBJECTIVES

Recombinant human growth hormone (rhGH) replacement therapy in children and adults currently requires daily subcutaneous injections for several years or lifelong. The current study examined safety, tolerability, pharmacokinetic and pharmacodynamic response parameters after single and multiple doses of a long-acting rhGH preparation (NNC126-0083).

DESIGN

Randomized, double-blinded, placebo-controlled, multiple-dose, dose-escalating (0·02, 0·04, 0·08 and 0·16 mg protein/kg), sequential dose group trial.

SUBJECTS

Forty adult Japanese healthy male volunteers (aged 20-45; body mass index: 18·0-27·0 kg/m(2)). Five groups (n = 8) were randomized to receive multiple doses of NNC126-0083 (n = 6) or placebo (n = 2).

METHODS

Primary outcome was safety, and tolerability of multiple doses of NNC126-0083 compared with placebo. Blood samples for the assessment of pharmacokinetics (PK) and pharmacodynamics response [insulin-like growth factor I (IGF-I) and IGF binding protein 3 (IGFBP-3)] were taken after multiple ascending doses.

RESULTS

NNC126-0083 was well tolerated and not associated with any local injection-site reactions or lipoatrophy. Following administration, NNC126-0083 levels increased rapidly and remained elevated for several days, returning to baseline before each weekly injection. Steady-state PK was achieved after the third dosing. A more than dose-proportional exposure was observed at the highest NNC126-0083 dose (0·16 mg protein/kg). A strong dose-dependent pharmacodynamic response in circulating concentrations of both IGF-I and IGFBP-3 compared with placebo (P < 0·0001) was observed during the administration of all doses.

CONCLUSIONS

Multiple administration of NNC126-0083 in healthy male volunteers indicates that NNC126-0083 has the potential for an efficacious, well-tolerated, once-weekly rhGH compound in the treatment of GH deficiency.

Retesting the childhood-onset GH-deficient patient

GH deficiency (GHD) in adults has to be shown by a single provocative test, provided that it is validated. Insulin tolerance test (ITT) has been indicated as the test of choice; now also glucagon test is validated and represents an alternative. The GHRH plus arginine (ARG) test and testing with GHRH plus a GH secretagogue are equally reliable diagnostic tools, and are now considered as 'golden' standards as ITT. Childhood-onset (CO) GHD needs retesting in late adolescence or young adulthood; this is a major clinical challenge and raises questions about the most appropriate method and cut-off value. Appropriate re-evaluation of GH status is represented by simple measurement of IGF1 concentration off rhGH treatment. Clearly, low IGF1 levels are evidence of persistent severe GHD in subjects with genetic GHD or panhypopituitarism. However, normal IGF1 levels never rule out severe GHD and CO-GHD with normal IGF1 levels must undergo a provocative test. The appropriate GH cut-off limit is specific for each provocative test. As shown by the ROC curve analysis, in late adolescents and young adults, the lowest normal GH peak response to ITT is 6.1 microg/l while that to GHRH+ARG test is 19.0 microg/l. These cut-off limits, however, are just indicative as being variable as a function of the assay used. No other test is validated for retesting. As GHRH+ARG test mostly explores the GH-releasable pool, normal GH response would be verified by a second ITT in order to rule out subtle hypothalamic defect.

[Management of the growth hormone (GH)-treated patients with diagnosis of GH deficiency (DGH) during transition from childhood to adulthood]

Growth hormone (GH) has many beneficial effects in patients with childhood-onset GH deficiency (GHD) in addition to its promotion of linear growth. The discontinuation of GH treatment in GHD patients, during the transition from childhood to adulthood, induces significant unfavorable changes in body composition, skeletal integrity, exercise capacity, and an adverse cardiovascular risk profile. These changes are reversed after the resumption of GH treatment. As the benefits of continuing GH therapy into adulthood has been well established, it is possible that GH replacement therapy will not be stopped once growth has been completed, but it will continue into adult life. Considering that a high proportion of patients with diagnosis of DGH in childhood are no longer GHD in adolescence, the GH status must be retested when growth is completed. Other factors such as clinical history, GH response in childhood, hipotalamic-pituitary MRI and IGF-1 concentration must be considered. Reconfirmation of GHD diagnosis through stimulation testing is usually required, unless there is a proven genetic or structural lesion persistent from childhood.

Subnormal serum insulin-like growth factor-I levels in young adults with childhood-onset nonacquired growth hormone (GH) deficiency who recover normal gh secretion may indicate less severe but persistent pituitary failure

CONTEXT

The unexpected observation of a normal GH peak in 22% of young adults with childhood-onset GH deficiency (GHD) and ectopic neurohypophysis has raised questions about the criteria defining GHD in young adults and whether patients with subsequent increases in GH secretion nonetheless have a subtle form of GHD.

OBJECTIVE

Our objective was to determine the characteristics of patients with childhood-onset nonacquired GHD who recover normal peak GH secretion when adult height has been achieved.

DESIGN AND SETTING

We conducted a university hospital-based observational follow-up study.

PARTICIPANTS

Sixty-two patients with ectopic neurohypophysis (n = 24), isolated hypoplastic anterior pituitary (n = 14), or normal hypothalamic pituitary area (n = 24) on magnetic resonance imaging (MRI) at the time of GHD diagnosis underwent reevaluation of the GH-IGF-I axis at a mean age of 16.8 +/- 1.6 yr.

MAIN OUTCOME MEASURES

Outcome measures included clinical and MRI findings and serum IGF-I and peak GH levels.

RESULTS

On retesting, peak GH exceeded 10 microg/liter in 31 patients (50%): six (20%) patients with ectopic neurohypophysis, 10 (32%) patients with initially isolated hypoplastic anterior pituitary, and 15 (48%) patients with normal MRI findings. Among these patients, serum IGF-I levels were significantly lower in patients with ectopic neurohypophysis than in those without structural abnormalities of the hypothalamic pituitary axis (n = 25), but patients without structural abnormalities also had significantly lower serum IGF-I levels than control subjects, after controlling for age, sex, and body mass index (mean serum IGF-I levels of 374 +/- 83 vs. 446 +/- 108 microg/liter; beta-coefficient = -72; P = 0.003).

CONCLUSIONS

The severity of the disease seems to have decreased over time in these patients, who may nonetheless present persistent pituitary failure. The natural history and clinical implications of these findings remain to be clarified. The possibility of a deterioration in the secretion of GH and other pituitary hormones later in life in a subset of these patients warrants the careful long-term follow-up of this population.

The advantage of measuring spontaneous growth hormone (GH) secretion compared with the insulin tolerance test in the diagnosis of GH deficiency in young adults

OBJECTIVE

Reassessment of GH status after the attainment of adult height has important clinical implications in the diagnosis and prognosis of GH deficiency (GHD) in adulthood. The current GH threshold for biochemical definition of GHD in young adults is still a subject of debate.

DESIGN

To investigate the role of pharmacological stimulation tests compared with spontaneous 12-h nocturnal GH secretion in the diagnosis of permanent GHD in young adults with childhood-onset GHD.

PATIENTS

Forty-five young adults (25 males, 20 females) with childhood-onset GHD, height standard deviation score (SDS) -1.1 +/- 1.3 and body mass index (BMI) SDS 1.0 +/- 1.6, were re-evaluated at the age of 19.8 +/- 2.7 years. Sixteen subjects showed a normal pituitary gland on magnetic resonance imaging (MRI), while in 29, consistent structural hypothalamic-pituitary abnormalities were found. GH secretion was assessed by means of an insulin tolerance test (ITT) and a 12-h spontaneous nocturnal profile as well as by IGF-I assessment. The results were compared with those of 43 healthy controls.

RESULTS

Mean 12-h spontaneous nocturnal GH secretion was < 3.1 microg/l (the lowest limit of the normal range) in 36 (80%) of the subjects and > 3.1 microg/l in nine (20%). Of these 36 patients, 29 (80%) had abnormal MRI findings and 20 (55%) had multiple pituitary hormone deficiencies (MPHD). All nine subjects with mean spontaneous GH secretion > 3.1 microg/l had a normal pituitary MRI, isolated GHD and a peak GH response to ITT > 5 microg/l. There was a discordance in 14 patients (31%), who showed a peak GH response to ITT > 5 microg/l but a reduced spontaneous GH secretory capacity; 10 had structural hypothalamic-pituitary abnormalities on MRI.

CONCLUSIONS

Although the ITT provides valuable information and proves to be a sensitive index of permanent GHD, the results of this study emphasize the potential diagnostic value of assessment of 12-h spontaneous GH secretion in young adults with childhood-onset GHD.

Defining Growth Hormone Status in Adults with Hypopituitarism

The identification of adults with severe growth hormone (GH) deficiency (GHD) is not straightforward. The insulin tolerance test remains the gold standard diagnostic test, although other stimuli such as GH-releasing hormone-arginine are gaining acceptance. Insulin-like growth factor-I has a poor diagnostic sensitivity in adult-onset GHD, but is more useful in the subgroup of adults with childhood-onset GHD. Therapeutic developments include increasing recognition of the need to continue GH therapy beyond final height in young adults with severe GHD on retesting. Consensus guidelines have provided a useful algorithm to identify individuals requiring retesting and the number of tests needed. The concept of partial GHD, recognized by paediatric endocrinologists for many years, is being examined in adults with hypothalamic-pituitary disease. Preliminary evidence suggests that this entity is associated with metabolic and anthropometric abnormalities intermediate between those in severe GHD and in healthy controls. It remains to be seen whether this subgroup will derive benefit from GH therapy. To date, therapeutic benefits of GH have been demonstrated only in adults with severe GHD. It is, therefore, imperative that these individuals are unequivocally identified; the diagnosis becomes more uncertain in the presence of obesity, increasing age, and in the absence of additional pituitary hormone deficits.

Growth hormone and the transition from puberty into adulthood

With modern growth hormone (GH) replacement algorithms, children with a diagnosis of growth hormone deficiency achieve at the end of pediatric GH treatment an adult height that is on the average in the normal range. Recent experience with GH replacement in young adults with childhood-onset growth hormone deficiency, however, has shown that these patients present with variable degrees of somatic immaturity. As childhood GH treatment is discontinued when final height is attained, attention moves to the phase of somatic development that follows the end of longitudinal growth, called ''transition'', which had been excluded previously from consideration for either pediatric or adult GH replacement. This article reviews the changes taking place during this phase of development and their relevance for the attainment of adult body maturation. The critical role of GH in this process is described.

Value of insulin-like growth factor system markers in the assessment of growth hormone status

Insulin-like growth factor-I (IGF-I) has been measured extensively in a variety of clinical settings. Total IGF-I frequently is used to assess the clinical impact of disorders of GH secretion and to monitor patients' response to therapy. It does not have sufficient precision to be used as a stand-alone test in the diagnosis of GH deficiency. Free IGF-I, IGF binding protein-3, or acid-labile subunit may provide useful information regarding GH secretion in specific conditions but are not superior to IGF-I for making the diagnosis of GH deficiency or acromegaly.

Are factors at diagnosis of growth hormone deficiency in childhood associated with persistence of growth hormone deficiency into adult life?

A proportion of children with growth hormone deficiency (GHD) have persistence of GHD as young adults. To date, no markers have been shown in childhood to have predictive value in determining persistence of GHD into adult life. We examined the hypothesis in 31 patients that variables present at the time of diagnosis of childhood-onset GHD, or those related to the early response to growth hormone (GH) therapy, are associated with the likelihood of persistence of GHD. The results show that, as previously demonstrated, children with GHD are more likely to have persistent severe GHD in adult life when the diagnosis is associated with other pituitary hormone deficiencies (p = 0.02), abnormal pituitary neuroimaging (p = 0.003), induced puberty (p = 0.001), early age of diagnosis (p = 0.03) and lower peak GH response at the first dynamic GH test in childhood (p = 0.02). However, there are no associations of persistent severe GHD with the pattern of pretreatment growth or growth response to GH treatment in the initial phase.

Diagnosis of GH deficiency in the transition period: accuracy of insulin tolerance test and insulin-like growth factor-I measurement

OBJECTIVE

A consensus exists that severe growth hormone deficiency (GHD) in adults is defined by a peak GH response to insulin-induced hypoglycemia (insulin tolerance test, ITT) of less than 3 microg/l based on a cohort of subjects with a mean age of 45 years.

DESIGN AND METHODS

By considering one of the following two criteria for the diagnosis of probable permanent GHD, i.e. the severity of GHD (suggested by the presence of multiple pituitary hormone deficiencies (MPHD)) or the magnetic resonance (MR) imaging identification of structural hypothalamic-pituitary abnormalities, 26 patients (17 males, 9 females, mean age 20.8 +/- 2.3 years, range 17-25 years) were selected for re-evaluation of the GH response to ITT and their IGF-I concentration. Eight subjects had isolated GHD (IGHD) and 18 had MPHD. Normative data for peak GH were obtained after ITT in 39 healthy subjects (mean age 21.2 +/- 4.4 years, range 15.1-30.0 years) and the reference range for IGF-I was calculated using normative data from 117 healthy individuals.

RESULTS

Mean peak GH response to ITT was significantly lower in the 26 patients (1.8+/-2.0 microg/l, range 0.1-6.1 microg/l) compared with the 39 controls (18.5 +/- 15.5 microg/l, range 6.1-84.0 microg/l; P < 0.0001). One subject with septo-optic dysplasia had a peak GH response of 6.1 microg/l that overlapped the lowest peak GH response obtained in normal subjects. There was an overlap for IGF-I SDS between subjects with IGHD and MPHD, as well as with normal controls. The diagnostic accuracy of a peak GH response of 6.1 microg/l showed a 96% sensitivity with 100% specificity. The maximum diagnostic accuracy with IGF-I SDS was obtained with a cut-off of -1.7 SDS (sensitivity 77%, specificity 100%) while an IGF-I < or = - 2.0 SDS showed a sensitivity of 62%.

CONCLUSION

Our data show that the cut-off value of the peak GH response to ITT of less than 3 microg/l or 5 microg/l and of IGF-I of less than -2.0 SDS are too restrictive for the diagnosis of permanent GH deficiency in the transition period. We suggest that permanent GHD could be investigated more accurately by means of an integrated analysis of clinical history, the presence of MPHD, IGF-I concentration and the MR imaging findings of structural hypothalamic-pituitary abnormalities.

Do all patients with childhood-onset growth hormone deficiency (GHD) and ectopic neurohypophysis have persistent GHD in adulthood?

Cerebral magnetic resonance imaging findings are of great value for the diagnosis of nonacquired GH deficiency (GHD), and ectopic posterior pituitary hyperintense signal (EPPHS) is a sensitive and specific indicator of hypopituitarism. It has been suggested that patients with childhood-onset GHD and EPPHS do not require additional investigation of GH secretion and should not be retested when adult height is achieved. This recommendation has never been validated through a systematic study. This study aimed to characterize the anterior pituitary function status of patients with EPPHS treated for GHD during childhood after completion of GH therapy when adult height had been achieved. Patients (n = 18; 15 males and three females) with childhood-onset GHD associated with ectopic neurohypophysis were treated with hGH (0.20 +/- 0.05 mg/kg.wk) for 9.9 +/- 4.0 yr (from 6.8 +/- 4.7 to 17.7 +/- 1.3 yr of age) with a mean height gain of 2.6 +/- 1.4 sd score. GH secretion was reevaluated by arginine insulin (n = 15) or propanolol glucagon (n = 3) test after 0.5 +/- 0.6 yr of GH withdrawal. At reevaluation, peak GH was more than 10 mug/liter in four patients (22%; range, 11.7-19.5 microg/liter; group I), between 5 and 10 microg/liter in three patients (17%; range, 7.3-9 mug/liter; group II), and less than 5 microg/liter in 11 patients (61%; range, 0-4.7 microg/liter; group III). A positive correlation was found between serum IGF-I and peak GH levels after attainment of adult height (P = 0.007). Only one of the seven patients who showed increased GH secretion ability in adulthood (groups I and II) demonstrated other hormonal deficiencies (gonadotropin and adrenal insufficiencies). Among the 11 patients with persistent severe GHD (group III), 10 (91%) of the 11 subjects were shown to have multiple pituitary hormone deficits after attainment of adult height. The structure of the hypothalamo-pituitary axis differs among groups [i.e. patients who showed increased GH secretion ability in adulthood (groups I and II) vs. those who remained severely GHD (group III)]. The location of the EPPHS was significantly different among groups (P < 0.003). The EPPHS was found at the median eminence in all but one of group III patients and along the pituitary stalk (proximal stalk) in all but one of group I and II patients. The pituitary stalk was visible and described as normal (n = 1) or thin (n = 6) in all group I and II patients, whereas the pituitary stalk was not visible even after enhancement in seven of the 11 group III patients (P < 0.02). The prevalence of anterior pituitary hypoplasia and the mean height gain sd score were similar in each group. In conclusion, only 61% of patients with childhood-onset GHD and EPPHS remained severely GHD, and thus suitable for GH therapy, in adulthood. Although the pathogenesis of anterior pituitary dysfunction remains unclear in patients with ectopic neurohypophysis, isolated GHD, location of EPPHS along the stalk, and visibility of the pituitary stalk on magnetic resonance imaging findings clearly represent important markers to predict a less severe form of the disease.

Studies of very severe short stature with severe GH deficiency: from the data registered with the foundation for growth science

The ratio, clinical characteristics, and therapeutic efficacy of hGH treatment in patients with severe short stature (HtSDS below -4SD) with severe GHD (all peak GH values to provocation tests: below 2 mug/L) were studied. From March 1986 to January 1998, 23,110 patients with idiopathic GH deficiency (IGHD) were registered with the Foundation for Growth Science, Japan. These subjects were divided into 5 groups as follows: Group 1 (G1), all subjects; Group 2 (G2), at least one GH peak to provocative test > or = 5 microg/L; Group 3 (G3), 2 microg/L < or = GH peak<5 microg/L; Group 4 (G4), all GH peaks<2 microg/L and HtSDS>-4; Group 5 (G5), all GH peaks<2 microg/L and HtSDS< or = -4. The ratio of G5 was 139 patients (0.6%) out of 23,110 patients with IGHD. In G5, there were no significant differences in birth weight, birth length, gestational age and parental height between G2, G3 and G4. However, asphyxia at delivery was more frequent in G5 and G4 than G2 and G3. Chronological age (CA), bone age (BA) and BA/CA ratio at registration were significantly lower in G5 than G2, G3 and G4. Further, the IGF-I SD score in G5 was significantly lower than those in G2 and G3. After hGH treatment, the final height and final height SDS in G5 remained the lowest, while the DeltaHtSDS value in G5 was the greatest among G2 to G5 groups. In conclusion, the ratio of severe short stature with severe GH deficiency (G5) is only 0.6% of all IGHD cases. Growth failure in G5 seems to occur after birth, and its etiology in G5 seems to be different from that of patients with other forms of IGHD. Early diagnosis and hGH treatment are needed to attain better final height.

Effect of growth hormone (GH) treatment on bone in postpubertal GH-deficient patients: a 2-year randomized, controlled, dose-ranging study

GH treatment in children with GH deficiency is frequently terminated at final height. However, in healthy individuals bone mass continues to accrue until peak bone mass is achieved. Because no prospective data specifically prove the role of GH in attainment of peak bone mass, we performed a multinational, controlled, 2-yr study in patients who had terminated pediatric GH at final height. Patients were randomized to: GH at 25.0 microg/kg x day (pediatric dose, n = 58) or 12.5 microg/kg x day (adult dose, n = 59), or no GH treatment (control, n = 32). Bone mineral content (BMC) and density were measured by dual-energy x-ray absorptiometry and evaluated centrally. Laboratory measurements were also performed centrally. After 2 yr, significant increases were seen with both GH treatments, compared with control in bone-specific alkaline phosphatase (P = 0.004) and type I collagen C-terminal telopeptide:creatinine ratio (P < 0.001), but there were no significant dose effects. Total BMC increased by 9.5 +/- 8.4% in the adult dose group, 8.1 +/- 7.6% in the pediatric dose group, and 5.6 +/- 8.4% in controls (analysis of covariance, P = 0.008), with no significant GH dose effect. BMC increased predominantly at the lumbar spine (11.0 +/- 10.6%, P = 0.015) rather than at the femoral neck or hip. In contrast, a significant dose-dependent increase was seen in IGF-I concentrations (adult dose: 114.5 +/- 119.4 microg/liter; pediatric dose: 178.5 +/- 143.7 microg/liter; P = 0.023). There were no gender-related differences in BMC changes with either dose, whereas the IGF-I increase was significantly higher with the pediatric than with the adult dose in females (P < 0.001) but not males (P = 0.606). In summary, reinstitution of GH replacement after final height in severely GH-deficient patients induced significant progression toward peak bone mass. Although there was a by-gender dose effect on IGF-I concentration, the treatment effect on bone was obtained in both males and females with the adult GH dose regimen.