Predictors of Adult Height in Girls with Turner Syndrome Treated with Growth Hormone † 408

Abstract

It is generally recognized that growth hormone (GH) therapy can improve the adult height of girls with Turner syndrome (TS). It has been difficult to quantify the ultimate effect of GH therapy on adult height and to examine the factors that might affect efficacy. Potential predictors of adult height include: age of initiation of GH therapy, frequency of GH injections, GH dose, age of initiation of estrogen therapy, height relative to age at initiation of GH therapy, bone age at initiation of GH therapy, parent heights, duration of GH therapy, and karyotype. In a clinical study in which 60 of 117 girls with TS began GH therapy before age 11 yrs, 30 of these girls were randomized to receive estrogen at age 12 and 30 at age 15. A comparison of treated girls with last measured height after age 13.5 yrs with untreated historical controls with heights obtained after 18 yrs showed a gain of 5.9 cm in the early estrogen group (n=26) and 8.3 cm in the late estrogen group (n=29)(ANCOVA p < 0.01 between groups). In a multiple regression analysis of adult height for girls with last height measured after age 16 yrs, the only significant predictor of adult height gain over expected adult height (based on the projection of childhood Turner-standardized height) was the number of years of GH therapy before initiation of estrogen therapy (n=29, p < 0.0001). The mean increase in adult height over expected was 2.1 cm for each year of GH therapy prior to estrogen therapy.