Thirteen studies were included in the review (the number of participants was not reported). Of the 13 studies, 11 were full publications and two were abstracts. One study was a cluster randomised randomised controlled trial (by hospital), another study was an interrupted time series and the rest were before-after studies with no contemporaneous control group. Most studies met few of the quality criteria.
There was no evidence of a difference in inpatient mortality, cardiopulmonary arrest or unscheduled admission to intensive care unit between the intervention and control groups in the RCT. Rapid response teams were associated with a reduction in inpatient mortality in the observational studies (risk ratio 0.82, 95% CI: 0.74 to 0.91). The I2 was 62%, indicating significant heterogeneity. The magnitude of the summary effect risk ratio for the observational studies subgroup was similar to the risk ratio for the control group in the RCT (risk ratio 0.73, 95% CI: 0.53 to 1.02). Rapid response teams were also associated with an improvement in the rate of cardiopulmonary arrests in the observational studies subgroup (risk ratio 0.73, 95% CI: 0.65 to 0.83) similar to the rate in the control group of the RCT (risk ratio 0.63, 95% CI: 0.48 to 0.82). There was no evidence of an effect of rapid response systems on unscheduled intensive care unit admissions in the observational studies (risk ratio 1.08, 95% CI: 0.96 to 1.22) with significant heterogeneity (I2 quantity 79%).