Background: Pediatric acute
appendicitis (PAA) involves a substantial consumption of health and economic resources. The identification of serum
biomarkers that may help predict the post-surgical evolution of these patients is a field of great interest. Patients and Methods: This was a prospective, observational substudy within the
Biomarkers for the Diagnosis of
Appendicitis in Pediatrics (BIDIAP) cohort aimed at evaluating the association between post-surgical increase in serum
IL-6 and different outcomes related to the clinical evolution of children operated on for PAA. Sixty-nine children with a confirmed diagnosis of acute
appendicitis and both pre-operative and post-operative serum
IL-6 were included in the study. Three multivariable-adjusted linear regression models were fitted to analyze the association between an increase of >10% in post-operative serum
IL-6 level with the
length of stay, the number of post-operative
emetic episodes, and the onset of oral feeding. Two multivariable-adjusted logistic regression models were fitted to assess the association of the same exposure with the indication of antibiotherapy at discharge and with positivity in peritoneal fluid culture. Results: Thirteen children showed an increase of >10% in the post-operative serum
IL-6 value (group 1) whereas 56 showed only a minor increase, or no change (group 2). After accounting for potential confounders, children in group 1 had a mean of three-day longer
hospital stay (difference, 3.33; 95% confidence interval [CI], 0.57-6.09) and higher odds of a positive result in peritoneal fluid culture (odds ratio [OR], 37.43; 95% CI, 1.02-1361.28) than children in group 2. Conclusions: An increase of >10% in post-operative serum
IL-6 value could predict longer
hospital stay and higher odds of positive peritoneal fluid culture. Future prospective studies are needed to replicate these findings and to broaden the range of
biomarkers that could predict the post-operative evolution of children operated on for PAA.