Growth hormone (GH)-deficiency in adults: clinical features and effects of GH substitution

Adherence in children with growth hormone deficiency treated with r-hGH and the easypod™ device

PURPOSE

Poor adherence to recombinant human growth hormone (r-hGH) therapy is associated with reduced growth velocity in children with growth hormone deficiency (GHD). This twelve-month observational study was to assess adherence in r-hGH patients treated with the easypod^™, an electronic, fully automated injection device designed to track the time, date and dose administered.

METHODS

Ninety-seven prepubertal patients receiving r-hGH therapy were included in the study from ten Italian clinical sites and 88 completed the study. To avoid possible confounding effects, only GHD patients (79/88; 89.7 % of the overall study population) were considered in the final analysis. The primary endpoint-adherence to treatment-was calculated as the proportion of injections correctly administered during the observational period out of the expected total number of injections. The relevant information, tracked by the easypod^™, was collected at months 6 (V1) and 12 (V2) after baseline (V0). At study termination, adherence data were partially available from 16 patients and fully available from 53 patients. As secondary endpoints, serum IGF-1 levels, fasting serum glucose and insulin levels and key anthropometric characteristics (height, waist circumference and BMI) were also determined.

RESULTS

The easypod^™ data showed that 56.7 % of the patients were considered to be fully (≥92 %) adherent to their treatment throughout the period V0-V2. Treatment improved stature, significantly increased IGF-1 and produced a non-significant increase in blood glucose and insulin levels.

CONCLUSIONS

The injection-recording system and other characteristics of easypod^™ could enhance the ability of physicians to monitor adherence to r-hGH treatment.

An observational study to validate the Satisfaction Measure of the Injection of Growth Hormone Therapy (SMIGHTy) questionnaire

OBJECTIVE

The objective of this study was to psychometrically evaluate a tool to measure adult caregivers' level of satisfaction with the delivery device used to administer injections of recombinant human growth hormone (rhGH) to a child - the Satisfaction Measure of the Injection of Growth Hormone Therapy (SMIGHTy*) questionnaire.

RESEARCH DESIGN AND METHODS

One hundred caregivers who administer rhGH to a child using an injection device completed the SMIGHTy questionnaire at baseline and 7-14 days later, and also completed other measures of treatment adherence and treatment satisfaction at baseline.

MAIN OUTCOME MEASURES

SMIGHTy reliability (inter-item and test-retest) and external validity (association with other study measures) were assessed.

RESULTS

Analyses revealed good inter-item agreement and test-retest reliability for the SMIGHTy questionnaire. External validity, measured by associations with adherence and other measures of treatment satisfaction, was high.

STUDY LIMITATIONS

This study assessed only adult caregivers; the instrument was not validated for use by young or adult patients.

CONCLUSIONS

The SMIGHTy instrument is more comprehensive than existing instruments for assessing the growth hormone treatment experience. It is multidimensional, assesses both positive and negative aspects of the treatment experience (Device Satisfaction, Negative Events, Benefits), and has separate measures of overall satisfaction and preference.

Treatment adherence with the easypod™ growth hormone electronic auto-injector and patient acceptance: survey results from 824 children and their parents

BACKGROUND

Accurately monitoring adherence to treatment with recombinant human growth hormone (r-hGH) enables appropriate intervention in cases of poor adherence. The electronic r-hGH auto-injector, easypod™, automatically records the patient's adherence to treatment. This study evaluated adherence to treatment of children who started using the auto-injector and assessed opinions about the device.

METHODS

A multicentre, multinational, observational 3-month survey in which children received r-hGH as part of their normal care. Physicians reviewed the recorded dose history and children (with or without parental assistance) completed a questionnaire-based survey. Children missing ≤2 injections per month (92% of injections given) were considered adherent to treatment. Adherence was compared between GH treatment-naïve and treatment-experienced children.

RESULTS

Of 834 recruited participants, 824 were evaluated. The median (range) age was 11 (1-18) years. From the recorded dose history, 87.5% of children were adherent to treatment over the 3-month period. Recorded adherence was higher in treatment-naïve (89.7%, n = 445/496) than in treatment-experienced children (81.7%, n = 152/186) [Fisher's exact test FI(X) = 7.577; p = 0.0062]. According to self-reported data, 90.2% (607/673) of children were adherent over 3 months; 51.5% (421/817) missed ≥1 injection over this period (mainly due to forgetfulness). Concordance between reported and recorded adherence was 84.3%, with a trend towards self-reported adherence being higher than recorded adherence. Most children liked the auto-injector: over 80% gave the top two responses from five options for ease of use (720/779), speed (684/805) and comfort (716/804). Although 38.5% (300/780) of children reported pain on injection, over half of children (210/363) considered the pain to be less or much less than expected. Given the choice, 91.8% (732/797) of children/parents would continue using the device.

CONCLUSIONS

easypod™ provides an accurate method of monitoring adherence to treatment with r-hGH. In children who received treatment with r-hGH using easypod™, short-term adherence is good, and significantly higher in treatment-naïve children compared with experienced children. Children/parents rate the device highly. The high level of acceptability of the device is reflected by a desire to continue using it by over 90% of the children in the survey.

Pain following controlled cutaneous insertion of needles with different diameters

BACKGROUND AND AIM

Needle injections are used daily by millions of people around the world for the administration of various drugs (e.g., insulin), venepuncture, and some neurophysiological procedures. The aim of this paper was to study the influence of the outer needle diameter on the pain evoked by controlled needle insertion.

METHODS

An automated needle injection system was used to perform a series of insertions where velocity, angle of insertion, and depth of injection were controlled. The frequency of pain following needle insertions (23G, 27G, 30G, 32G) was recorded together with the pain intensity (measured using the visual analogue scale--VAS) and the occurrence of bleeding.

RESULTS

The outer needle diameter was positively and significantly correlated to the frequency of the insertion pain; for example, 63% of insertions with 23G needles caused pain, 53% of insertions with 27G and 31% of insertions with the thinnest (32G) needle (p < 0.0001) caused pain. The thickest needle caused most insertions associated with bleeding. Bleeding insertions were approximately 1.3 times more painful (as indicated by VAS scores) than insertions without concomitant bleedings (p = 0.004).

CONCLUSION

By decreasing the outer diameter of a needle, the frequency of insertion pain can be reduced and may encourage patients to adhere to demanding injection regimens such as recurrent insulin administration.

Growth hormone receptor expression and function in pituitary adenomas

OBJECTIVE AND DESIGN

Hypopituitarism, in particular GH deficiency, is prevalent in patients with clinically nonfunctioning pituitary adenomas (NFPAs) both before and after surgery. The factors regulating the growth of pituitary adenomas in general and residual tumour tissue in particular are not fully characterized, and the effect of GH and IGF-I on human pituitary cell proliferation has not previously been reported. In NFPA tissue from 14 patients we evaluated GH receptor (GHR) expression and signal transduction, and the effect of GH and IGF-I exposure on cell proliferation and hormone secretion in vitro.

MEASUREMENTS

Tissue samples from 14 NFPAs were investigated. Expression of GHR in tissue samples was assessed by reverse transcription polymerase chain reaction (RT-PCR). Six tumours were immunostained with a GHR antibody. In the cell cultures, STAT5 (signal transducer and activator of transcription 5) phosphorylation was measured by Western blot analysis as an index of GHR signalling; cell proliferation was evaluated by [H3]-thymidine incorporation and glycoprotein hormone production analysed by radioimmunoassay (RIA).

RESULTS

All adenomas investigated expressed the GHR, but there was no detection of STAT5 phosphorylation. Overall, GH and IGF-I administration did not significantly stimulate cell proliferation in vitro, although some individual adenomas exhibited a proliferative response to various extents. GH also did not significantly influence glycoprotein hormone secretion in vitro.

CONCLUSION

GH receptors are expressed in human pituitary adenoma cells but their functional role is uncertain. GH and IGF-I do not consistently influence the proliferation of cultured pituitary adenoma cells.

Pharmacokinetics and acute lipolytic actions of growth hormone. Impact of age, body composition, binding proteins, and other hormones

The biologic actions of endogeneous growth hormone (GH) depend on its secretion and clearance rates as well as sensitivity at the receptor level. Aberrations in GH pharmacokinetics and pharmacodynamics may occur with increasing age, and have been implicated in diseases such as obesity, diabetes mellitus, and critical illness. In this review, recent insights into the association between GH metabolism and age, body composition, binding proteins and other hormones are discussed.

Growth hormone treatment for growth hormone deficient adults

Growth hormone (GH) deficiency in adults is now recognized as a clinical syndrome with characteristic signs and symptoms. Numerous trials with daily subcutaneous biosynthetic human growth hormone (hGH) have been conducted in this patient group. Generally, improvements in insulin-like growth factor levels, decreases in total fat mass and increases in lean body mass are recorded with no overall effect on total body weight. Variable effects on serum cholesterol, bone mineral density and quality of life have also been reported. The true place of GH replacement therapy in adults has yet to be defined. Several questions relating to the dose, duration of treatment, long-term side-effects, quality of life changes and health economic implications of treatment still need to be assessed.

Pain assessment of subcutaneous injections

OBJECTIVE

To compare injection pain after subcutaneous administration of four different solution volumes.

DESIGN

Double-blind, randomized, prospective, multiple crossover study.

SETTING

Steno Diabetes Center, Gentofte, Denmark.

PARTICIPANTS

Eighteen healthy volunteers, 9 women and 9 men, aged 21-30 years.

METHODS

The subjects were injected with four different volumes (0.2, 0.5, 1.0, 1.5 mL) of NaCl 0.9%. The study was performed on 2 days with a 1-week washout period between the study days. On each study day the subjects received four injections in each thigh. To evaluate the validity of our pain assessing model the subjects received eight injections of 0.5% mL on one of the study days. Pain assessment was done immediately after each injection using both a 10-cm visual analog scale (VAS) and a six-item verbal rating scale (VRS).

RESULTS

A significant difference in pain score on both the VAS (p < 0.05) and the VRS (p < 0.01) was seen between the four injection volumes. The pain was significantly increased with volumes of 1.0 and 1.5 mL. No significant difference in injection pain could be detected between 0.2 and 0.5 mL and between 1.0 and 1.5 mL. No significant period or carryover effect could be detected in the study. A significant correlation between the pain score on the VAS and the pain score on the VRS was found (r = 0.79, p < 0.0001).

CONCLUSIONS

The pain of a subcutaneous injection is related to injection volume in the thigh. The results show that increasing the volume from 0.5 to 1.0 mL increases the pain significantly. The findings from this study should be considered when injection preparations for subcutaneous administration are formulated. The volume should generally be less than 1.0 mL if injected into the thigh.

Fuel metabolism in growth hormone-deficient adults

Apart from being a stimulator of longitudinal growth, growth hormone (GH) regulates fuel metabolism in children and adults. A halfmark is mobilization of lipids, which involves an inhibition of lipoprotein lipase activity in adipose tissue and activation of the hormone sensitive lipase. Suppression of basal glucose oxidation and resistance to insulin are other important effects. This may cause concern during GH substitution in GH-deficient adults, some of whom may present with insulin resistance due to concomitant abdominal obesity. However, there are data to suggest that the GH-induced reduction in fat mass and increase in lean body mass may offset the insulin antagonistic actions of the hormone. The nitrogen-retaining effects of GH seem to involve a direct stimulation of protein synthesis in addition to secondary effects such as generation of insulin-like growth factor-I (IGF-I), hyperinsulinemia, and promotion of lipolysis. Thus, during periods of substrate affluence, GH acts in concert with insulin and IGF-I to promote protein anabolism. Postabsorptively, GH is primarily lipolytic and thereby indirectly protein-sparing. This effect becomes further accentuated with more prolonged fasting. In that sense, GH is unique by its preservation of protein during both feast and famine. These fuel metabolic effects add merit to the principle of GH substitution in hypopituitary adults.

Patient evaluation of a new injection pen for growth hormone treatment in children and adults

The aim of this study was to evaluate patients' perception and acceptance of a new multi-dose injection device (Genotropin Pen) for recombinant growth hormone (GH) supplied in a two-chamber cartridge. The pen is combined with a very thin needle (B-D Microfine + (29 G) and meets future demands when dosing of GH will be changed from International Units (IU) to milligrams (mg). A total of 39 children receiving GH treatment (East Hospital, Gothenburg and St Bartholomew's Hospital, London), aged between 7 and 17 years, and 39 GH-treated adults (Sahlgrenska Hospital, Gothenburg and Karolinska Hospital, Stockholm), aged between 20 and 68 years, participated in the study. The daily dose ranged from 0.3 mg to 2.6 mg. The injections were given subcutaneously, once daily, and most of the patients used the thigh as an injection site. After a trial period of 2 weeks, injection technique, pain, fear of injection and convenience of the Genotropin Pen were compared with the experience with the prestudy device (Genotropin KabiPen 16, 16(8) or 36) by questionnaire. A total of 95% of the patients preferred the Genotropin Pen to the prestudy device for the following reasons: a greater certainty of correct dosing with the digital display; the possibility of correcting the set dose; the lock function of the injection button when injection is complete; more comfortable to hold due to the design and the plastic material; and reduced pain when injecting due to the thinner needles. Four patients (5%) preferred the prestudy device KabiPen as they considered this to be 'good enough'. Thus, the Genotropin Pen is a convenient injection device and most patients prefer it to the KabiPen.