Predictors of a histopathologic diagnosis of complicated appendicitis

Background Despite its utilization, the intraoperative (IO) assessment of complicated appendicitis (CA) is subjective. The histopathologic (HP) diagnosis should be the gold standard in identifying patients with CA; however, it is not immediately available to guide postoperative management. The objective of this study was to identify predictors of an HP diagnosis of CA. Materials and methods A retrospective review of all patients who underwent appendectomy at our institution from 2011-2013 was conducted. CA was defined by perforation or abscess on pathology report. Predictors of an HP diagnosis of CA were evaluated using a multivariable regression model. Results A total of 239 of 1066 patients had CA based on IO assessment, whereas 143 of 239 patients (60%) had CA on HP and IO assessment. On multivariable analysis, an IO diagnosis of CA was associated with an HP diagnosis of CA (odds ratio [OR]: 10.92; 95% confidence interval [CI]: 7.19-16.58). Other risk factors were age (OR: 1.28; 95% CI: 1.09-1.49), number of days of pain (OR: 1.20; 95% CI: 1.07-1.37), increased heart rate (OR: 1.14; 95% CI: 1.02-1.26), appendix size (OR: 1.09; 95% CI: 1.03-1.16), and an appendicolith (OR: 1.74; 95% CI: 1.12-2.71) on preoperative CT imaging. Conclusions In addition to age, increased heart rate, pain duration, appendix size and appendicolith, the IO assessment is also associated with an HP diagnosis of CA; however, 40% of patients were incorrectly classified. Using these predictors with improved IO grading may achieve more accurate diagnosis of CA.