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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Effects of rapid response systems on clinical outcomes: systematic review and meta-analysis

SR Ranji, AD Auerbach, CJ Hurd, K O'Rourke, and KG Shojania.

Review published: 2007.

Link to full article: [Journal publisher]

CRD summary

This review assessed effectiveness of rapid response systems to reduce inpatient mortality, inpatient cardiac arrest and unscheduled visits to the intensive care unit in hospitalised patients. It found insufficient evidence to recommend rapid response systems due to the substantial limitations of the included studies. The authors' negative conclusions appear appropriate.

Authors' objectives

To evaluate the effects of rapid response systems on inpatient mortality, inpatient cardiac arrest and unscheduled transfer to an intensive care unit in hospitalised patients.


MEDLINE, CINAHL and BIOSIS Previews were searched for relevant studies up until August 2006. The starting dates for the searches were not reported. Studies were restricted to those in the English language. Search terms were reported and the full search strategy was included in an appendix. The abstract lists from the 2004 and 2005 American Thoracic Society and Society of Critical Care Medicine annual meetings, and reference lists from key articles were searched.

Study selection

Randomised controlled trials, controlled before-after studies and interrupted time series were eligible for inclusion. Studies were required to report the effects of a rapid response system on at least one of the outcomes inpatient mortality, inpatient cardiac arrest (as defined in the study) and unscheduled transfer to an intensive care unit (as defined in the study). A rapid response system was defined by the authors as a system that used a standard set of clinical criteria for intervention whenever hospitalised patients become unstable before cardiopulmonary arrest occured. Inclusion criteria relating to participants were not clearly specified.

The included studies were all conducted in teaching hospitals in Australia, United States or United Kingdom. The studies mostly included hospitalised adults; pediatric inpatients were included in two studies. Studies mostly assessed the effects of the rapid response systems on all hospitalised patients, but subgroups of patients and outpatients were also included. The rapid response teams mostly included both specialist nurses and medical doctors, but the protocols for response to specific clinical criteria differed across studies.

Two reviewers independently assessed the articles for inclusion in the review. Disagreements were resolved either by consensus or by discussion with a third reviewer.

Assessment of study quality

The authors assessed the internal validity of the included studies according to domains derived from a consensus statement on medical emergencies, the Cochrane EPOC group and published recommendations. Elements that described the generalisability of the studies were derived by consensus of the authors. A composite quality score was not calculated, but categories (yes, no or not reported) for each domain were reported separately for each study.

Two reviewers independently assessed the internal validity of the included studies.

Data extraction

Data were extracted on inpatient mortality, inpatient cardiopulmonary arrests and unscheduled intensive care unit admissions before and after the introduction of rapid response teams. Risk ratios were calculated with 95% confidence intervals (CIs). Data were also collected on the rapid response system calling rates and the number of admissions, where possible. For RCTs that reported both pre- and post-intervention data, intervention and control groups were treated as separate trials in order to compare results with the before-after studies. The authors did not state whether they needed to collect missing information.

Two reviewers independently extracted data from the included studies.

Methods of synthesis

The authors used a random-effects model to combine data in a meta-analysis and calculate summary risk ratios. Subgroup analysis was undertaken for RCTs and observational studies. For studies that reported results adjusted for clustering, the unadjusted results were back calculated. Heterogeneity was assessed by the I2 quantity. The authors did not report whether they undertook sensitivity analyses or analyses to check for publication bias.

Results of the review

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%).

Authors' conclusions

The effectiveness of the rapid response system concept remained unproven.

CRD commentary

The review addressed a clear research question and inclusion criteria were appropriate, although eligibility criteria for participants were not specifically defined. Several relevant sources were searched to identify relevant studies and efforts were made to find further information by reviewing references lists and handsearching conference abstracts, but the exclusion of non-English language studies may have meant relevant studies were missed. Publication bias was not assessed. Methods were used to minimise bias and reviewer error in the selection of studies, but it was not stated whether similar methods were used for data extraction and quality assessment, so bias and error during these processes could not be ruled out. The included studies had substantial methodological weaknesses. The significant statistical heterogeneity in the pooled analyses indicated that the variability between individual studies in treatment effects may be greater than that expected by chance. The reasons for this heterogeneity were not further explored. Given the substantial flaws of the included studies, the authors' cautious conclusion is appropriate.

Implications of the review for practice and research

Practice: The authors stated that hospitals should not be mandated to establish rapid response system teams.

Research: The authors stated that future studies should attempt to define which patient populations were at risk, the essential characteristics of rapid response systems, effective implementation strategies and whether any rapid response systems improve clinical outcomes.


Not stated.

Bibliographic details

Ranji SR, Auerbach AD, Hurd CJ, O'Rourke K, Shojania KG. Effects of rapid response systems on clinical outcomes: systematic review and meta-analysis. Journal of Hospital Medicine 2007; 2(6): 422-432. [PubMed: 18081187]

Indexing Status

Subject indexing assigned by NLM


Emergency Medical Services /methods /trends; Humans; Randomized Controlled Trials as Topic /methods /trends; Treatment Outcome



Database entry date


Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 18081187


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