The use of C-reactive protein to predict uncomplicated appendicitis and increase uptake of laparoscopy in low resource hospitals-A retrospective cohort study.

Background: Acute appendicitis remains the most common surgical emergency worldwide. There has been a low uptake of laparoscopic appendicectomy in the South African public sector. Preoperative identification of cases of uncomplicated appendicitis that are amenable to a laparoscopic approach may facilitate the implementation of laparoscopic appendicectomy programs in training hospitals. With limited access to preoperative imaging, alternative strategies for this preoperative prediction are needed.

Methods: A retrospective audit of patients over the age of 12 years with a histologically confirmed diagnosis of acute appendicitis over a 5-year period was performed. Patients were categorized as uncomplicated or complicated appendicitis and C-reactive protein (CRP) and white cell count (WCC) reviewed. Receiver operating characteristics curves were constructed for these blood tests and acute appendicitis severity. Youden's J statistic was used to determine optimal cut off values for diagnosing complicated appendicitis.

Results: 358 patients had confirmed appendicitis and complete blood results. Of these, 189 (52.79%) had complicated appendicitis with a 40.22% perforation rate. Median CRP in uncomplicated and complicated groups were 68 mg/L (IQR 19-142) and 216 mg/L (IQR 103-313) with an area under the curve (AUC) of 0.75 (95% CI: 0.70-0.80). The median WCC in the two groups were 12.6 × 10 cells/L (IQR 9.9-15.6) and 14.4 × 10 cells/L (IQR 11.5-18.28) with an AUC of 0.61 (95% CI: 0.56-0.67). The optimal cut off value for CRP was found to be 110 mg/L with a sensitivity of 74.74% and specificity of 69.23%.

Conclusion: A cutoff value of 110 mg/dl CRP can distinguish patients with early appendicitis from those with complicated disease and when used in conjunction with clinical assessment may help identify patients in whom laparoscopic appendicectomy is appropriate.