Study design for final height determination in Turner syndrome: pros and cons

Early studies on the use of human growth hormone (hGH) for the treatment of Turner syndrome are reviewed and attention is drawn to the higher dose used compared with the doses for growth hormone deficiency (GHD). Patients with Turner syndrome responded less consistently than GHD patients to hGH. The prediction of final height in Turner syndrome from bone age is uncertain - long-term trials are essential to resolve final height questions. The pros and cons of randomized placebo-controlled trials, randomized nontreatment-controlled trials and historical controlled trials are compared, and it is concluded that in the USA, a randomized placebo-controlled trial is the most appropriate study design. The ethical considerations of such a long-term trial, in terms of risk vs. benefit, and the need for a placebo-treated group are also discussed.