ESPE Abstracts

Objectives: Response to rGH during the first year of treatment is considered indicative of its effectiveness for the improvement of final height. The iGRO software assesses the response to rGH in children with idiopathic growth hormone deficiency (IGHD) or small for gestational age (SGA) based on age, gender, gestational age, birthweight, rGH dose, maximal GH during stimulation tests, as well as weight and height measurements on follow-up visits. The aim was to evaluate the response to rGH and assess the iGRO software as to the prediction of height velocity (HV) during the first year of treatment.

Methods: Retrospective study of preadolescent children monitored at the Endocrinology Department of "P&A Kyriakou" Children’s Hospital with IGHD or SGA before and one year after the start of the rGH treatment. Variables recorded in the iGRO were analyzed, as well as the index-derived response rate (IoR), calculated as (observed HV-predicted HV)/standard deviation of predicted HV. IoR <-1.28 indicates low response, i.e. lower response compared to the corresponding reference population, while IoR >1.28 a better than expected response. For the comparison of the variables between groups, the x2 and one way ANOVA tests were used (STATA version 13.1).

Results: In total, 118 children (73 boys) were studied, mean age 7.66 (2.01) years, of which 92.4% with IGHD. A percentage of 78% (n=92) had a good response i.e. the observed growth rate agreed with that predicted by the software (-1.28<IoR<1.28), while 15.3% (n=18) had a worse response and 6.78% (n=8) a better response than that predicted. Among the 3 response-based groups, there was no difference in gender, age at treatment initiation, median height, baseline BMI z-score, diagnosis (IGHD/SGA), peak GH in stimulation tests and the initial rGH dose. Children with good responsiveness had a tendency for lower initial height z-score compared to children with low responsiveness (P=0.085). Children with poor responsiveness had a higher initial predicted growth rate [9.15 cm (1.9)] than children with normal [(8.4 (1.15)]) and good responsiveness [8.1 (0.7)] (P=0.022). The actual growth rate was 6.7 (1.5), 8.2 (2.1) and 10.1 (10.1) cm, p <0.001, respectively.

Conclusion: In our population, high rates of good response indicate a correct application of the clinical criteria for the diagnosis of IGHD. The iGRO software provides realistic expectations of treatment outcome, is easy to use in daily clinical practice and can detect patients with an unsatisfactory response who need re-evaluation of the diagnosis.