Using preoperative C-reactive protein levels to predict anastomotic leaks and other complications after elective colorectal surgery: A systematic review and meta-analysis.

Aim: While postoperative C-reactive protein (CRP) is used routinely as an early indicator of anastomotic leak (AL), preoperative CRP remains to be established as a potential predictor of AL for elective colorectal surgery. The aim of this systematic review and meta-analysis is to examine the association between preoperative CRP and postoperative complications including AL.

Method: MEDLINE, EMBASE, Web of Science, PubMed, Cochrane Library and CINAHL databases were searched. Studies with reported preoperative CRP values and short-term surgical outcomes after elective colorectal surgery were included. An inverse variance random effects meta-analysis was performed for all meta-analysed outcomes to determine if patients with or without complications and AL differed in their preoperative CRP levels. Risk of bias was assessed with MINORS and certainty of evidence with GRADE.

Results: From 1945 citations, 23 studies evaluating 7147 patients were included. Patients experiencing postoperative infective complications had significantly greater preoperative CRP values [eight studies, n = 2421 patients, mean difference (MD) 8.0, 95% CI 3.77-12.23, p < 0.01]. A significant interaction was observed with subgroup analysis based on whether patients were undergoing surgery for inflammatory bowel disease (X = 8.99, p < 0.01). Preoperative CRP values were not significantly different between patients experiencing and not experiencing AL (seven studies, n = 3317, MD 2.15, 95% CI -2.35 to 6.66, p = 0.35), nor were they different between patients experiencing and not experiencing overall postoperative morbidity (nine studies, n = 2958, MD 4.54, 95% CI -2.55 to 11.62, p = 0.31) after elective colorectal surgery.

Conclusion: Higher preoperative CRP levels are associated with increased rates of overall infective complications, but not with AL alone or with overall morbidity in patients undergoing elective colorectal surgery.