Title: Evidence synthesis in rare diseases
Authors: Tim Friede - University Medical Center Goettingen (Germany) [presenting]
Abstract: Meta-analyses in rare diseases (also called orphan diseases) and small populations generally face particular problems, including small numbers of studies, small study sizes and heterogeneity of results. However, the heterogeneity is difficult to estimate if only very few studies are included. Motivated by a systematic review in immunosuppression following liver transplantation in children the characteristics of commonly used frequentist and Bayesian procedures for random effects meta-analyses will be explored and recommendations for their practical applications will be made. This will also include the common case of meta-analyses including only two studies. We will extend the meta-analytic methods to generalized evidence synthesis or cross design synthesis considering the special case of combing a randomized controlled trial with a non-randomized study, i.e. data from a clinical registry. This part is motivated by a clinical research project in Creutzfeldt-Jakob disease.