Should we start and continue growth hormone (GH) replacement therapy in adults with GH deficiency?

During the last decade, growth hormone deficiency (GHD) in adults has been described as a clinical syndrome. Central features of this entity include increased fat mass, reduced muscle and bone mass, as well as impaired exercise capacity and quality of life. GH replacement therapy has been initiated on a wide scale, but patients do not profit equally from this expensive therapy. The decision to start and continue GH replacement should be made individually for each patient. An eligible patient should have a clear diagnosis of GHD. In addition, GH replacement therapy should be efficacious. Especially, the unique and valuable effects of GH replacement on exercise performance and quality of life are strong arguments in favour of continuation of therapy. In osteopenic patients, GH replacement increases bone mass. Also, GH induces improvements in the cardiovascular risk profile. However, it has not yet been proved whether GH replacement reduces the incidence of bone fractures and cardiovascular mortality and improves life expectancy. Thus far, long-term physiological GH replacement does not appear to be complicated by adverse effects. Therefore, available evidence warrants continuation of long-term GH replacement therapy in patients with a clear-cut diagnosis of GHD who demonstrate beneficial effects of this therapy, especially with regard to exercise performance and quality of life.