Preoperative risk factors associated with anastomotic leakage after colectomy for colorectal cancer: a systematic review and meta-analysis
Bibliographic record
Abstract
INTRODUCTION: anastomotic leak (AL) after colectomy for colorectal cancer (CRC) is a life-threatening complication. This systematic review and meta-analysis aimed to evaluate the preoperative risk factors for AL in patients submitted to colectomy. METHODS: the bibliographic search covered 15 years and 9 months, from 1st January 2005 to 19th October 2020 and was performed using PubMed, Cochrane Library, Scopus, Biblioteca Virtual em Saúde, Europe PMC and Web of Science databases. The inclusion criteria were cross-sectional, cohort and case-control studies on preoperative risk factors for AL (outcome). The Newcastle-Ottawa scale was used for bias assessment within studies. Meta-analysis involved the calculation of treatment effects for each individual study including odds ratio (OR), relative risk (RR) and 95% confidence intervals (95% CI) with construction of a random-effects model to evaluate the impact of each variable on the outcome. Statistical significance was set at p<0.05. RESULTS: cross-sectional studies were represented by 39 articles, cohort studies by 21 articles and case-control by 4 articles. Meta-analysis identified 14 main risk factors for AL in CRC patients after colectomy, namely male sex (RR=1.56; 95% CI=1.40-1.75), smoking (RR=1.48; 95% CI=1.30-1.69), alcohol consumption (RR=1.35; 95% CI=1.21-1.52), diabetes mellitus (RR=1.97; 95% CI=1.44-2.70), lung diseases (RR=2.14; 95% CI=1.21-3.78), chronic obstructive pulmonary disease (RR=1.10; 95% IC=1.04-1.16), coronary artery disease (RR=1.61; 95% CI=1.07-2.41), chronic kidney disease (RR=1.34; 95% CI=1.22-1.47), high ASA grades (RR=1.70; 95% CI=1.37-2.09), previous abdominal surgery (RR=1.30; 95% CI=1.04-1.64), CRC-related emergency surgery (RR=1.61; 95% CI=1.26-2.07), neoadjuvant chemotherapy (RR=2.16; 95% CI=1.17-4.02), radiotherapy (RR=2.36; 95% CI=1.33-4.19) and chemoradiotherapy (RR=1.58; 95% CI=1.06-2.35). CONCLUSIONS: important preoperative risk factors for colorectal AL in CRC patients have been identified based on best evidence-based research, and such knowledge should influence decisions regarding treatment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.013 | 0.035 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.020 | 0.037 |
| Bibliometrics | 0.007 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".