Dawid Pieper

Cochrane reviews are known to be a high‐quality source of evidence synthesis supporting health care decisions. In a recently conducted study, we analyzed the trends in epidemiology and reporting of published systematic reviews over the last 20 years. This sample of 1132 systematic reviews included 84 Cochrane reviews. We have learned several peculiarities of Cochrane reviews that are worth being discussed in more detail due to their practical implications. Methodologists, clinicians and health care professionals should be aware of these limitations: (1) Cochrane reviews are not identified as systematic reviews in title, (2) Cochrane reviews do not always follow PRISMA reporting guidelines, (3) Some updates are only available via the Cochrane Library, and (4) Indexing of Cochrane reviews in PubMed may be suboptimal.

Aim This systematic review and meta‐analysis aimed to investigate the effect of preoperative stoma site marking on stoma‐related complications in patients with intestinal ostomy. Methods MEDLINE, Embase, CENTRAL, CINHAL, and Google Scholar were searched up to August 2021 for randomised controlled trials (RCTs) and nonrandomised studies of interventions (NRSI) that involved patients with intestinal ostomies comparing preoperative stoma site marking to no marking and which reported at least one patient‐relevant outcome. Outcomes were prioritised by stakeholder involvement. Random‐effects meta‐analyses produced odds ratios (ORs) or standardised mean differences (SMD) and 95% confidence intervals (CIs). The ROBINS‐I tool and the GRADE approach were used to assess the risk of bias and certainty of evidence, respectively. Results This review included two RCTs and 25 NRSI. The risk of bias was high in RCTs and serious to critical in NRSI. Although preoperative site marking reduced stoma‐related complications (OR: 0.45, 95% CI: [0.31–0.65]), dependence on professional or unprofessional care (narrative synthesis), and increased health‐related quality of life (SMD: 1.13 [0.38–1.88]), the evidence is very uncertain. Preoperative site marking may probably reduce leakage (OR: 0.14 [0.06–0.37]) and may decrease dermatological complications (OR: 0.38 [0.29–0.50]) and surgical revision (OR: 0.09 [0.02–0.49]). The confidence in the cumulative evidence was moderate to very low. Conclusion Despite low quality evidence, preoperative stoma site marking can prevent stoma‐related complications and should be performed in patients undergoing gastrointestinal surgery given that this intervention poses no harm to patients.