Epidemiologic studies on acute appendicitis in children

Acute appendicitis is the most common surgical emergency in children. A considerable effort has been made to develop and improve treatment and outcomes. A PubMed search yields over 20 000 publications on appendicitis. Almost 8 000 abstracts are found if the search is restricted to children. Nevertheless, there are still controversies on the diagnostic work-up, treatment and outcome of acute appendicitis and there are many issues to be further explored. The diagnostic process behind the decision to explore the abdomen and remove the diseased appendix is evolving and novel diagnostic modalities are continuously introduced. Appendectomy as gold standard treatment for simple and complex appendicitis is challenged by non-operative treatment options. Even the fundamental concept of appendicitis as an inevitably progressive disease, ending up in perforation, has been challenged. We have not been able to fully understand nor significantly reduce associated complications including appendiceal perforation, intra-abdominal abscess, postoperative wound infection and adhesive small bowel obstruction, leading to significant morbidity and even death. The general aims of this thesis were to investigate the epidemiology of acute appendicitis in children and to identify factors important for optimising treatment and reducing morbidity. Paper I was a retrospective cohort study investigating the correlation between in-hospital surgical delay and the risk for perforated appendicitis. All 2 756 children operated for acute appendicitis in our institution 2006‒2013 were included in the study. Secondary outcome measures were markers of postoperative complications. In multivariate logistic regression analysis, increased time to surgery was not associated with increased risk for histopathologic perforation. There was no correlation between the timing of surgery and rate of postoperative wound infection, intra-abdominal abscess, reoperation, or readmission. In paper II, the epidemiology of acute appendicitis and appendectomy was investigated in a population-based cohort of Swedish children. Data was collected from the Swedish National Patient Register (NPR). 64 971 children registered in the NPR 1987‒2013 were eligible for the study. A rapidly declining incidence rate of childhood appendicitis was identified in Sweden over the study period, with significantly different trends comparing non-perforated and perforated appendicitis. Incidence rates differed between genders and between health care regions. Data did not reveal explanations on the aetiology of the findings. In paper III, the correlation between provision of care and outcome after appendectomy in children was investigated. Data from the NPR on 55 591 childhood appendectomies in Sweden 1987‒2009 were analysed. The risk of postoperative complications was significantly reduced in specialised paediatric surgical centers and in high caseload hospitals, compared to other hospitals. There were only seven deaths within 90 days of appendectomy in the cohort. We concluded that provision of care matters, and that reduced risks for complications may not only be achieved by centralisation to paediatric surgical centers but also by increasing hospital caseload of childhood appendicitis management in other settings