All studies that applied the UK four-hour target (98% of patients discharged or admitted within four hours of arrival) in an emergency department setting and that reported on at least one outcome other than time target were eligible for inclusion. Outcomes had to be measured before and after introduction of the final target in 2004.
Included studies were from the UK NHS setting and presented both hospital-level and NHS aggregated data. Outcomes included emergency department presentations, time to seeing a treating clinician, treatment within one hour, times to paediatric analgesia and X-ray radiograph for hip fracture in older patients, orthopaedic/trauma surgery wait time, number of tests per patient, admissions for less than 24 hours, return visits within seven or 30 days of emergency department attendance and mortality.
Two independent reviewers carried out the study selection. Disagreements were resolved by consensus.