The Effects of Growth Hormone Treatment Discontinuation in Adults on Metabolic Profile, Body Composition and Quality Of Life (GAMBOL Study)

Plain-language summary

Background Growth hormone (GH) is a hormone produced by the pituitary gland which sits at the base of the brain. In adults, GH plays an important role in keeping the bones and muscles healthy, and in regulating the levels of sugar and fat in the body. Growth hormone deficiency (GHD) is a condition where the pituitary gland does not make as much GH as the body needs. The most common cause is damage to the pituitary gland due to tumours (growth), surgery or radiotherapy. In the UK, around 1 in 10,000 adult people have GHD. If left untreated, adults with GHD may experience tiredness and low mood, develop weaker bones, have increased body fat and high cholesterol. Research has shown that treatment with daily GH injections can improve the symptoms experienced by patients with GHD, but the beneficial effects of GH treatment have only been studied over a short period of 4 to 12 months. In the UK, most adults with GHD are prescribed with GH indefinitely. Some adult patients, who have been on GH treatment for a long time, have wondered what would happen if they stopped taking GH. Will their symptoms come back or not? At the moment, there is no research evidence that clearly answer this question. Hence, a systematic investigation is urgently needed to examine what happens when adult patients with GHD stop taking GH. Aims The main aim of this study is to establish if it would be feasible to conduct a robust and systematic study called a randomised control trial (RCT), to compare the effects of continuing and stopping long-term GH treatment in adult patients with GHD. This study will: (1) assess whether patients taking GH injection, would agree to take part in a study involving stopping their GH injection and being monitored over a period of time and (2) whether patients would be willing to stop or continue their GH injections by chance (random selection) if accepted in the study. Methods This project includes three separate studies: * Phase 1: Online national survey of UK GHD specialists treating adult patients with GHD. * Phase 2: Feasibility study involving two groups of adult patients with GHD who have been receiving GH treatment for at least 5 years. Patients will be recruited from two GHD specialist centres in Birmingham. One group (intervention) will include 20-25 patients who are willing to stop taking GH treatment for 2 years. The second group (control) will include 20-25 patients who wish to continue their GH treatment and are willing to undergo monitoring for 2 years. The monitoring will involve blood tests and completing quality of life questionnaires every 6 months, and measurements of body fat, muscles mass and bone mineral density at the beginning and at the end of the study. * Phase 3: Face-to-face or telephone interviews with 10-16 patients to explore in detail their experiences of participating, completing and/or withdrawing from the study. Patient and Public Involvement A patient and public advisory group has helped design this proposal and will be involved throughout the research project. The group will review the study protocol, help develop the necessary information resources for participants and assist with interpretation of the results. Dissemination The results of the study will be submitted for publication in medical journals in the field of GHD. The results will also be presented at the Pituitary Foundation meetings and at local, national and international conferences. Members of the patient and public advisory group will also help in sharing the information about the study with the wider public through relevant charities and social media.

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