Patients with complicated appendicitis were significantly older (51 vs. 31 years, p < 0.001), had a higher BMI (24.2 vs. 25.8 kg/m2, p < 0.001), worse ASA score (p < 0.001), a higher prevalence of diabetes (8 vs. 3%, p > 0.001), higher CRP value (117 vs. 22 mg/l, p < 0.001), and a higher prevalence of intraabdominal fluid on preoperative sonography (54 vs. 31%, p < 0.001). This evidence concerns the gene CRP and diabetes mellitus.