Growth Hormone Dosing Estimations Based on Body Weight Versus Body Surface Area.

(rhGH) replacement. The aim was to compare the two regimens to determine if either resulted in inadequate treatment depending onanthropometric factors.Methods: The retrospective study included children diagnosed with idiopathic isolated growth hormone deficiency. BW-based dosing inmcg/kg/day was converted to BSA in mg/m2/day to determine the equivalent amounts of the given rhGH. Those with a BW-to-BSA ratioof more than 1 were allocated to the “relatively over-dosed group”, while the remaining patients with a ratio of less than 1 were assignedto the “relatively under-dosed” group. Patients with a height gain greater than 0.5 standard deviation score (SDS) at the end of one yearwere classified as the height gain at goal (HAG), whereas those with a height gain of less than 0.5 SDS were assigned as the height gainnot at goal (NHAG).Results: The study included 60 patients (18 girls, 30%). Thirty-six (60%) patients were classified as HAG. The ratio of dosing based onBW-to-BSA was positively correlated both with the ages and body mass index (BMI) levels of the patients, leveling off at the age of 11 ata BMI of 18 kg/m2. The relative dose estimations (over- and under-dosed groups) differed significantly between the patients classifiedas HAG or NHAG. Fifty-six percent of NHAG compared to 44% of HAG patients received relatively higher doses, while 79% of HAGcompared to 21% of NHAG received relatively lower doses (p=0.006). When the patients were subdivided according to their pubertalstatus, higher doses were administrated mostly to the pubertal patients in both the NHAG and HAG groups. In the pre-pubertal agegroup, 73% of NHAG compared to 27% of HAG received relatively higher doses, while 25% of NHAG compared to 75% of HAG receivedrelatively lower doses (p=0.01).Conclusion: Dosing based on BW may be preferable in both prepubertal and pubertal children who do not show adequate growthresponses. In prepubertal children, relatively lower doses calculated based on BW rather than BSA provide similar efficacy at lower costs.Keywords: Body surface area, body weight, growth hormone, IGF-1, IGFBP-3, pharmacotherapy