The authors concluded that no single intervention or bundle of interventions appeared to reliably reduce risk for 30-day rehospitalisation in patients. This conclusion reflects the evidence presented, but potential bias in the search, variation among the included studies, and the impact of limited study quality suggest that it should be interpreted with caution.

To evaluate interventions to reduce the rehospitalisation of patients within 30 days of discharge.

MEDLINE, EMBASE, Web of Science, and the Cochrane Library were searched from 1975 to January 2011 for articles published in the English language. Search terms were reported. Reference lists of reviews and included studies were scanned and experts were contacted for additional studies.

Studies of non disease-specific interventions (with the aim of reducing rehospitalisation) versus no intervention that reported on readmission within 30 days of discharge were eligible for inclusion. Studies of paediatric, obstetric and psychiatric patients were excluded.

Twelve intervention categories were identified in the included studies. The interventions were classified in temporal sequence: pre-discharge interventions (patient education, discharge planning, medication reconciliation, appointment scheduled before discharge); post-discharge interventions (timely primary care provider communication, timely clinic follow-up, follow-up telephone call, post-discharge hotline, and home visit); and interventions bridging the transition between hospital and home (transition coach, patient-centred discharge instruction, and provider continuity). Most included studies focussed on a single intervention, but few of these were tested with a randomised design. Other studies evaluated various components contained within a discharge bundle. Intervention descriptions and context were not well described. Patients were from various clinical populations. Most studies were conducted in the USA; two studies were conducted in the UK.

Two reviewers selected the studies for inclusion. Disagreements were resolved through discussion between four reviewers.

Study quality was assessed using an adapted version of the Cochrane Effective Practice and Organisation of Care (EPOC) risk of bias tool. Nine criteria were assessed including randomisation, allocation concealment, similarity of baseline characteristics, outcome assessment, handling of missing data, and likelihood of contamination between study groups.

Two reviewers independently assessed study quality. Disagreements were resolved by discussion.

Data were extracted to enable calculation of percentage absolute risk reduction.

The authors did not explicitly state how many reviewers extracted the data.

A narrative synthesis was provided. Results were grouped according to the temporal classification of interventions (as described earlier).

Forty-three studies were included in the review. There were 16 randomised controlled trials (RCTs), with sample sizes ranging from 34 to 835 patients. There were 20 quasi-experimental/cohort studies and seven non-controlled before-and-after studies (although the quality assessment table showed 14 controlled clinical studies and 13 non-controlled studies). Overall, study quality was limited. RCTs scored an average of 5 on the EPOC criteria; they were largely non-pragmatic and nine out of 16 had small sample sizes. Quasi-experimental/cohort studies scored an average of 4 on EPOC criteria; 14 out of 27 non-randomised studies had differences in baseline characteristics likely to impact on the outcome. Most included studies did not account for missing data or incomplete outcome assessment.

Five RCTs showed statistically significant reductions in 30-day rehospitalisation. One trial (835 high-risk patients) reported an 11% absolute risk reduction in favour of discharge planning over usual care.

Four trials (n=1,671 patients) that evaluated multi-component discharge bundles showed absolute risk reductions of 3.6%, 6%, 12%, and 28%. Post-discharge telephone call and patient-centred discharge instruction were common features of all four trials.

Eleven RCTs did not demonstrate any statistically significant effect of single-component or multi-component interventions.

Further results, including those from observational studies, were reported in the paper.

No single intervention or multi-component intervention implemented was regularly associated with reduced risk for 30-day rehospitalisation.

The review addressed a clear question. The inclusion criteria were potentiallly reproducible, although broad for study design. A number of relevant data sources were accessed, although language and publication biases could not be ruled out. The review process included attempts to minimise error and bias at all stages apart from data extraction.

An appropriate quality assessment tool was applied; the results of this were clearly reported and used in the discussion of review findings. Statistical heterogeneity was not assessed, but substantial clinical variation was clear amongst the predominantly observational studies; this suggested that the chosen method of synthesis was appropriate. Study details were provided. There appeared to be some discrepancy between tabulated data in the classification of study design. The authors drew attention to other reporting limitations.

The authors' conclusion reflects the evidence presented. However, potential bias in the search, clinical and methodological variation among the included studies, and the impact of limited study quality (particularly the non-pragmatic nature and small sample size of RCTs) suggest that the conclusion should be intepreted with caution.

Practice: The authors stated that current evidence may not be adequate to facilitate change in hospitals, and planned penalties for rehospitalisation may be a reasonable course of action.

Research: The authors stated that future research is needed to identify patient-centred outcomes in relation to remedies for avoidable rehospitalisation, together with clearly defined successful implementation strategies.

Northwestern University Feinberg School of Medicine.

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.