Whether primary etiology of childhood-onset growth hormone deficiency (GHD) influences subsequent outcomes and response to GH replacement therapy in adulthood remains unclear.OBJECTIVE
To characterize primary etiology of GHD in adults with childhood onset of disease and to assess the effect of 2 years' GH-replacement therapy during adulthood.DESIGN AND INTERVENTION
This was a retrospective analysis of data derived from the Pfizer International Metabolic Database (KIMS), a survey of GH therapy in adults with GHD. Inclusion criteria included availability of baseline data and at least 2 years' GH treatment during adulthood. GHD was defined as either a peak GH level <3 μg/l after insulin-induced hypoglycemia or an insulin like growth factor-I SD score (IGF-I SDS) <−2 plus a peak GH level <3 μg/l after arginine or glucagon stimulation. Eligible participants were subclassified into three groups according to the primary etiology of GHD. The nonorganic pituitary disorder group comprised patients with congenital and idiopathic GHD in the absence of destructive lesions of the hypothalamus or pituitary gland. The organic pituitary disease group comprised patients with GHD caused by a tumor distant to the hypothalamic-pituitary region (e.g. neuroblastoma)OUTCOME MEASURES
The main outcome measures were weight, BMI, blood pressure, waist-to-hip ratio, waist circumference, lipid profile, IGF-I SDS, and health-related quality of life (HRQOL) score at baseline and after 2 years' GH therapy.RESULTS
The study assessed a total of 189 men and 164 women who met the inclusion criteria. Overall, 147 patients were diagnosed with nonorganic pituitary disorder (125 with idiopathic disease), 159 patients had organic pituitary disease (87 with craniopharyngioma), and 47 patients had GHD as a result of brain tumor (14 with medullo-blastoma). GHD was diagnosed ∼3 years later in the organic pituitary disease group than in the other two groups and so resulted in a shorter duration of GH therapy during childhood. By contrast, GH therapy during adulthood was initiated earlier in the brain tumor group than in the other two groups. Several between-group differences in the baseline measures were observed. Final height, waist circumference and BMI were greatest in the organic pituitary group. IGF-I SDS was lowest in the nonorganic pituitary disorder group, whereas HRQOL was most impaired in the brain tumor group. Panhypopituitarism was most common in the nonorganic and organic disease groups. By contrast, patients in the brain tumor group were more likely to have isolated GHD. IGF-I SDS, lipid profile and HRQOL improved in all groups after 2 years' GH therapy.CONCLUSION
Adult outcomes of childhood-onset GHD varied by primary etiology; however, GH therapy resulted in similar improvements in disease symptoms, regardless of the initial cause.