Linear growth response to growth hormone therapy in underweight versus normal weight short children

Abstract

Introduction Physiologically, growth hormone (GH) increases lean body mass and has a lipolytic function. However, long-term changes in weight status during GH treatment, as a function of pretreatment weight status have not previously been reported in large data sets. Aim To identify the growth response to GH therapy in those who were before treatment underweight versus normal weight short children. Patients and methods A retrospective study, we studied the auxologic data of 78 short, prepubertal children [height standard deviation score (HtSDS) less than −2 SDS below the mean for age and sex] with normal GH secretion [idiopathic short stature (ISS)]. Two groups were identified according to their pretreatment body mass index standard deviation score (BMISDS). Nineteen children were underweight (BMISDS < −2) and 59 children had normal BMISDS (>−2). All children received daily subcutaneous dose of GH (0.03–0.05 mg/kg/day) to keep their insulin-like growth factor-1 (IGF-1) level between 0 and 2 SD for 2 years. Results Before GH treatment, the underweight ISS group had significantly lower IGF-1 level versus the normal weight group with IGF-1 SD −1.633±0.766 SD versus −0.749±1.197 SD, respectively. Age and HtSDS did not differ among the two underweight and normal weight groups. Treatment with GH for 2 years was associated with a significant increase in the BMISDS in the underweight group (BMISDS increased by 0.45 SD) from −2.063±0.344 before treatment with GH versus −1.633±0.766 after treatment but not in the normal weight group. The HtSDS increased significantly in both groups after GH therapy, but the increase was greater in children with normal weight versus those with underweight as the increment in HtSDS was 0.42 and 0.374 SD, respectively. The difference of HtSDS from mid-parental HtSDS in low BMI versus normal BMI groups was −0.91 and −1.212 SD, respectively Conclusions GH therapy for 2 years significantly increased the IGF-1 level and improved BMISDS and HtSDS in underweight children with ISS. The BMISDS was better in the underweight group, but their HtSDS was less compared with the normal weight group.