Fever was significantly (p < 0.001) more common in the fistula group, and ratios (POD 7 to 3) of WBC, CRP, neutrophils, and neutrophils-to-lymphocytes (NLR) were significantly higher (all p ≤ 0.001) in the fistula group than in the no fistula group. Here, CRP is linked to Fever.