Seasonal and day of the week variations of perforated appendicitis in US children.

Purpose: The present study aimed to determine whether children with perforated appendicitis were more likely to present during specific days of the week or seasons of the year.

Methods: After obtaining IRB exemption, a retrospective, population-based study of patients <18 with ICD9 codes of acute (540.9) or perforated (540.0, 540.1) appendicitis in the Kids' Inpatient Database (KID) was performed. Univariate and multivariate analyses were performed analyzing patient and hospital factors.

Results: A total of 31,457 children were identified with acute appendicitis, of whom 10,524 (33.5%) were perforated. Mondays [odds ratio (OR): 1.16; 95% Confidence Interval (CI): 1.05-1.28] were significant for increased likelihood as day of presentation with perforation in US children more than any other day of the week. In seasonal analysis, fall (OR: 1.12; 95% CI: 1.04-1.21) and winter (OR: 1.11; 95% CI: 1.03-1.20) were at higher odds for perforation at presentation. Patients with Medicaid (OR: 1.22; 95% CI: 1.03-1.43) and those uninsured (OR: 1.50; 95% CI: 1.16-1.93) were more likely to present with perforation.

Conclusion: Perforated appendicitis was more likely to present on Mondays in US children. Although appendicitis is most common in summer months, rates of perforated appendicitis were highest in fall and winter.