The impact of general practitioners working in or alongside emergency departments: a rapid realist review.

Worldwide, emergency healthcare systems are under intense pressure from ever-increasing demand and evidence is urgently needed to understand how this can be safely managed. An estimated 10%-43% of emergency department patients could be treated by primary care services. In England, this has led to a policy proposal and £100 million of funding (US$130 million), for emergency departments to stream appropriate patients to a co-located primary care facility so they are 'free to care for the sickest patients'. However, the research evidence to support this initiative is weak.