Short stature: new challenges in growth hormone therapy

Until recently, the limited supplies of pituitary derived growth hormone (GH) enabled us to treat only those patients who were classical GH deficient. With the unlimited supplies of recombinant GH available, there is no limitation to the number of patients we can treat. It becomes necessary, however, to select those patients who will most benefit from GH therapy. Our preliminary results demonstrate that the short-term growth response to growth hormone is not an all-or-none phenomenon. The lower the growth velocity and the growth hormone reserve, the better the growth response to therapy. On the other hand we do not recommend institution of GH therapy for children with a normal growth rate and a normal GH spontaneous secretion. In children with classical GH deficiency (GHD) and in children with a subnormal spontaneous secretion of GH (NSD) adult height prediction decreases when GH therapy is started at an age older than 12. We have found that GHD and NSD boys differ in their growth pattern. Pubertal maturation and bone age maturation progress more rapidly in NSD patients. Therefore special caution is needed in NSD patients older than 12 years. The older the patient and the longer the treatment period, the faster the pubertal process can advance. Further studies are needed before recommendations for therapy in non-classical GHD patients can be made. Until patients involved in clinical trials reach final height, recommendations for new indications cannot be made.