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

Meta-analysis of randomized studies evaluating chewing gum to enhance postoperative recovery following colectomy

S Purkayastha, HS Tilney, AW Darzi, and PP Tekkis.

Review published: 2008.

CRD summary

The authors concluded that the evidence suggested that gum chewing following abdominal surgery may reduce the duration of postoperative ileus, but that more research was needed as the finding was based largely on small unblinded studies. The review was in most respects well conducted and the conclusions appear reliable.

Authors' objectives

To evaluate the effect of postoperative chewing gum for abdominal surgery patients.

Searching

EMBASE, The Cochrane Library and MEDLINE (including PubMed related articles) were searched up to July 2006 without language restriction. Search terms were reported. The reference lists of articles retrieved were handsearched.

Study selection

Randomised controlled trials (RCTs) of the use of chewing gum after abdominal surgery were eligible for inclusion, provided they were conducted in the early postoperative period and that they reported return to normal bowel function (that is, number of days to first passage of flatus and first postoperative bowel motion) and/or length of hospital stay (days from surgery to discharge).

All participants in the included studies had had open or laparoscopic colectomy. The mean age in each study was about 56 to 68 years. Approximately 40 per cent of participants were female. The intervention groups chewed sugarless gum three times a day postoperatively for (when reported) between five and 45 minutes. Some studies explicitly allowed oral fluids before the passage of flatus and some included patients with stomas, but this was not clearly reported in all studies.

The authors stated neither how the papers were selected for the review nor how many reviewers performed the selection.

Assessment of study quality

Study validity was assessed using the Jadad scale. A score of 3 or more points (out of 5) was considered high quality. The authors did not state how the assessment was performed.

Data extraction

The mean differences between the groups were calculated, with 95% confidence intervals (CIs). Intention to treat analysis was used where possible. Two reviewers independently extracted the data.

Methods of synthesis

Studies were pooled using both fixed- and random-effects models to calculate weighted mean differences (WMD) with 95% CIs, weighted by sample size. Statistical heterogeneity was assessed using the Χ2 test. Publication bias was assessed with funnel plots. Differences between the studies were explored with sensitivity analyses by quality score, sample size, publication year, type of surgery (open/laparoscopic) and whether patients with stomas were included explicitly.

Results of the review

Five RCTs were included in the review (n=158, sample size 19 to 43). One study had a Jadad score of 4, two scored 3 and two scored 2. Only one RCT used blinding of observers and included a placebo group. Only one study clearly accounted for dropouts.

Chewing gum versus controls (five RCTs)

Pooling of RCTs using a random-effects model found that the time to first passage of flatus and first bowel movement were both significantly shorter in the intervention group (WMD -0.66 days, 95% CI: -1.11 to -0.20, p=0.005 for flatus and WMD -1.10, 95% CI: -1.79 to -0.42, p=0.002 for bowel movement). However, both analyses had statistically significant heterogeneity2 test p<0.001). Findings for duration of hospital stay were not statistically significant.

The results of sensitivity analyses were also reported.

Results of a fixed-effect model were similar. Funnel plots showed no indication of publication bias.

Authors' conclusions

The evidence suggested that gum chewing following abdominal surgery may reduce the duration of postoperative ileus, but that more research was needed as the finding was based largely on small unblinded studies.

CRD commentary

The objectives and inclusion criteria of the review were clear. Relevant sources were searched for studies without language restriction. It was unclear whether the review was limited to published studies, but formal assessment did not provide evidence of publication bias. Steps were taken to minimise the risk of bias and error by having more than one author extract data, but it was unclear whether this applied also to study selection and validity assessment. Although the Jadad scale covers some basic aspects of study validity, it has limitations and some important characteristics of quality (such as allocation concealment) were not reported. The statistical techniques used to pool data appeared appropriate, and suitable methods were used to assess for heterogeneity and publication bias. Potential sources of heterogeneity were explored with sensitivity analyses and in the text. The authors acknowledged that the evidence was suggestive only, as it was limited by heterogeneity, suboptimal study design and small samples. The review was in most respects well conducted and the authors’ conclusions appear reliable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that a large, blinded placebo-controlled trial was needed to show whether gum chewing reduced duration of hospital stay after abdominal surgery. An RCT with 80 patients in each arm would have 80 per cent power to show a difference between the two groups of 1.25 days (in hospital stay).

Funding

Not stated.

Bibliographic details

Purkayastha S, Tilney H S, Darzi A W, Tekkis P P. Meta-analysis of randomized studies evaluating chewing gum to enhance postoperative recovery following colectomy. Archives of Surgery 2008; 143(8): 788-793. [PubMed: 18711040]

Indexing Status

Subject indexing assigned by NLM

MeSH

Chewing Gum; Colectomy /adverse effects; Defecation; Flatulence; Gastrointestinal Motility; Humans; Intestinal Pseudo-Obstruction /etiology /therapy; Length of Stay; Postoperative Period; Randomized Controlled Trials as Topic; Recovery of Function

AccessionNumber

12008105885

Database entry date

15/07/2009

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: 18711040

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