Reevaluation of Growth Hormone Deficiency During and After Growth Hormone (GH) Treatment: Diagnostic Value of GH Tests and IGF-I and IGFBP-3 Measurements

Abstract

Retesting of patients with growth hormone (GH) deficiency (GHD), especially those with idiopathic GHD, has yielded normalization of the results in several studies. The aim of this study was to reevaluate patients diagnosed as GHD at completion or reconfirm the diagnosis before completion of GH treatment by retesting with provocative tests, and to evaluate the value of IGF-I and IGFBP-3 levels in the diagnosis of GHD. Fifty (33 M, 17 F) patients with GHD (peak GH level <0.46 pmol/l (10 ng/ml]) in two pharmacological tests were retested and IGF-I and IGFBP-3 levels measured. The age of the patients at retest was 15.2+/-5.0 yr. Thirteen of 50 patients (26%) normalized their GH secretion. According to the initial diagnosis, 69% of those with partial GHD (peak GH level 0.32-0.46 pmol/l [7-10 ng/ml]), 43% with isolated GHD, 33% idiopathic and 11% of those with complete GHD (peak GH level <0.32 pmol/l [7 ng/ml]) normalized their GH level at retesting. None of the patients with multiple hormone deficiency and none with small pituitary on MRI normalized GH levels at retest. The sensitivities of IGF-I and of IGFBP-3 were 70% and 67%, respectively, and the specificities were 100%, when peak GH cutoff is taken as 0.46 pmol/l (10 ng/ml) for the diagnosis of GHD. The sensitivities of IGF-I and IGFBP-3 increased to 76.5% and 73.5% when the cutoff level for GHD is taken as 0.32 pmol/l (7 ng/ml). Those patients who normalized their GH levels at retest showed a satisfactory height velocity when GH therapy was discontinued. In conclusion, reevaluation of GH status may also be undertaken while patients are still on treatment as well as at completion of treatment, especially in patients with idiopathic, partial and isolated GHD, by retesting and by IGF-I and IGFBP-3 measurements. Lowering the cutoff level of GH peak at pharmacological tests to 0.32 pmol/l (7 ng/ml) will lower the number of false positive results in the diagnosis of GHD.

Natural History of Growth Hormone Deficiency in a Pediatric Cohort

“…Similar to previous studies, we report a high recovery rate in children with partial GHD [15,23]. Compared to the study of Tauber et al [15], including a similar cohort of 131 children with GHD (i.e.…”

“…Salient issues include the optimal test and cutoffs, GH immunoassay sensitivity, and clinical outcomes in patients with or without treatment. Also, the time of retesting warrants further examination, as Darendeliler et al [23] demonstrated that 69% of children with partial GHD recover prior to completion of growth. As summarized in table 1, stimulation tests have a huge variability in cutoff values depending on age and test used.…”

Is Adrenocorticotropic Hormone Deficiency Really Rare in Patients with Idiopathic Growth Hormone Deficiency and Normal Thyroid Function Tests

“…Improvement may occur before achieving final height, necessitating early retesting in childhood for the continuation of expensive GH therapy [19]. In our study, GHD was improved in 56% of patients at early retesting, after nearly 3.2 years of therapy.…”

Beneficial Effects of High Doses of Cabergoline in the Treatment of Giant Prolactinoma Resistant to Dopamine Agonists: A Case Report with a 21-Year Follow-Up

“…It is known that some patients who have GH deficiency and received treatment present normal values when submitted to new stimulation tests [35]. In addition, the fact that the patient had a large tumor could have compromised his GH secretion level.…”