A systematic review and meta-analysis of the applicability of clinical trial evidence to realworld patients

Decisions about which treatment to use are largely based on evidence from randomised controlled trials. However, these trials are usually carried out in highly selected groups of people, raising questions about how applicable such evidence is to the whole range of real-world patients. Groups commonly excluded are older people, women, people with other conditions or taking many unrelated drugs, and people with limited life expectancy for any reason. As a result, for some conditions it is known that the majority of people with the condition are excluded from the trials which determine guideline recommendations. However, although a number of individual studies in this area have been published, there has never been a systematic review of them all, and so the extent to which applicability is a general problem is uncertain. This project will complete such a systematic review and the findings will be of wide interest to research funders, clinicians and guideline developers.