INDICATIONS FOR OPERATION IN SUSPECTED APPENDICITIS AND INCIDENCE OF PERFORATION

Objective-To clarify poorly understood epidemiological features of app endicitis. Design-Retrospective study of consecutive cases from a defi ned population and analysis of data from published studies. Setting-Co unty of Jonkoping, Sweden. 3029 patients who underwent operation in 19 84-9 and 4717 patients from the county town who underwent operation in 1970-89, all for suspected appendicitis, plus 48 426 cases from six r eported studies. Main outcome measures-Incidences specific for age and sex and temporal trends of perforating and non-perforating appendicit is and removal of a normal appendix. Associations between diagnostic a ccuracy, rate of perforation, and incidences of removal of a normal ap pendix and of perforating and non-perforating appendicitis. Results-Th e incidence of appendicitis was 116/100000 inhabitants. Appendicitis w as more common in male patients. The incidence of perforating appendic itis was independent of age, stable over time, and uninfluenced by the rate of laparotomy, whereas the incidence of non-perforating appendic itis was age dependent, decreasing over time, and related to the diagn ostic accuracy and rate of removal of a normal appendix. Conclusions-P erforating and non-perforating appendicitis seem to be separate entiti es, and appendicitis that resolves spontaneously is common. This may h ave important implications for managing suspected appendicitis.