C-reactive Protein and Procalcitonin Levels to Predict Anastomotic Leak After Colorectal Surgery: Systematic Review and Meta-analysis.

Background: Anastomotic leak (AL) is a feared complication after colorectal surgery. Prompt diagnosis and treatment are crucial. C-reactive protein (CRP) and procalcitonin (PCT) have been proposed as early AL indicators. The aim of this systematic review was to evaluate the CRP and CPT predictive values for early AL diagnosis after colorectal surgery.

Methods: Systematic literature search to identify studies evaluating the diagnostic accuracy of postoperative CRP and CPT for AL. A Bayesian meta-analysis was carried out using a random-effects model and pooled predictive parameters to determine postoperative CRP and PCT cut-off values at different postoperative days (POD).

Results: Twenty-five studies (11,144 patients) were included. The pooled prevalence of AL was 8% (95 CI 7-9%), and the median time to diagnosis was 6.9 days (range 3-10). The derived POD3, POD4 and POD5 CRP cut-off were 15.9 mg/dl, 11.4 mg/dl and 10.9 mg/dl respectively. The diagnostic accuracy was comparable with a pooled area under the curve (AUC) of 0.80 (95% CIs 0.23-0.85), 0.84 (95% CIs 0.18-0.86) and 0.84 (95% CIs 0.18-0.89) respectively. Negative likelihood ratios (LR-) showed moderate evidence to rule out AL on POD 3 (LR- 0.29), POD4 (LR- 0.24) and POD5 (LR- 0.26). The derived POD3 and POD5 CPT cut-off were 0.75 ng/ml (AUC = 0.84) and 0.9 ng/ml (AUC = 0.92) respectively. The pooled POD5 negative LR (-0.18) showed moderate evidence to rule out AL.

Conclusions: In the setting of colorectal surgery, CRP and CPT serum concentrations lower than the derived cut-offs on POD3-POD5, may be useful to rule out AL thus possibly identifying patients at low risk for AL development.