Accuracy and limitations of the growth hormone (GH) releasing hormone-arginine retesting in young adults with childhood-onset GH deficiency

Background: Re-testing for GH secretion is needed to confirm the diagnosis of GH deficiency (GHD) after adult height achievement in childhood-onset GHD (COGHD). Aim: To define the cut-off of GH peak after retesting with GH-releasing hormone plus arginine (GHRHarg) in the diagnosis of permanent GHD in COGHD of different etiology. Patients and methods: Eighty-eight COGHD (median age 17.2 y), 29 idiopathic GHD (IGHD), 44 cancer survivors (TGHD) and 15 congenital GHD (CGHD) were enrolled in the study; 54 had isolated GHD (iGHD) and 34 had multiple pituitary hormone deficiencies (MPHD). All were tested with insulin tolerance test (ITT) and GHRHarg. IGHD with a GH response to ITT 656\ub5g/L were considered true negatives and served as the control group, and patients with a GH response <6\ub5g/L as true positives. Baseline IGF-I was also measured. The diagnostic accuracy of GHRHarg testing and of IGF-I SDS in patients with GHD of different etiologies was evaluated by ROC analysis. Results: Forty-six subjects with a GH peak to ITT 656\ub5g/L and 42 with GH peak <6 \ub5g/L showed a GH peak after GHRHarg between 8.8\u2013124\ub5g/L and 0.3\u201326.3\ub5g/L, respectively; 29 IGHD were true negatives, 42 were true positives and 17 with a high likelihood GHD showed a GH peak to ITT 656\ub5g/L. ROC analysis based on the etiology indicated the best diagnostic accuracy for peak GH cutoffs after GHRHarg of 25.3 \ub5g/L in CGHD, 15.7 in TGHD, and 13.8 in MPHD, and for IGF-1 SDS at 122.1 in CGHD, 121.5 in TGHD, and 121.9 in MPHD. Conclusions: Our findings indicate that the best cut-off for GH peak after retesting with GHRHarg changes according to the etiology of GHD during the transition age. Based on these results the diagnostic accuracy of GHRHarg remains questionable

Prevalence and correlates of adherence in children and adolescents treated with growth hormone: A multicenter Italian study

Objective: To evaluate the self-reported prevalence of poor adherence to recombinant human growth hormone (rhGH) therapy in a large, representative sample of Italian children and adolescents and to assess treatment and patient level correlates of poor adherence. Methods: The study was conducted in 46 pediatric centers throughout Italy. A questionnaire was administered to consecutive children/adolescents treated with rhGH or their parents. Eligible patients were represented by subjects aged between 6 and 16 years, of both sexes, on rhGH treatment for at least 6 months. The questionnaire was administered to the person in charge of preparing the injection. Multivariable logistic regression analysis was performed to identify factors independently associated with adherence. Results: Overall, 1,007 children/adolescents were involved, of whom 24.4% missed 1 or more injections during a typical week and were thus considered as nonadherent. The most frequently reported reasons for missing a dose were being away from home (33.3%), forgetfulness (24.7%), not feeling well (12.9%), and pain (10.3%). Multivariable analysis indicated association between poor adherence and adolescence, low level of parent education, longer duration of treatment, need to convince the child to inject, and low level of awareness of the consequences of not properly following treatment. The likelihood of adherence markedly increased with higher levels of perceived device convenience. Conclusion: Poor adherence is still a major problem in the treatment of growth disorders. Increasing awareness and reassessment of treatment adherence on an annual basis should be part of clinical practice of pediatric endocrinologists involved with rhGH treatment