Acute appendicitis incidence not randomly distributed

(HealthDay)—Socioeconomic status and other geographically defined factors are associated with incidence of acute appendicitis (AA), according to a study published online March 4 in JAMA Surgery.

Reece A. Golz, from the Boston University School of Medicine, and colleagues used data from Washington state's Comprehensive Hospital Abstract Reporting System (2008 to 2012) and the 2010 U.S. Census to identify population-based incidences of AA and perforated appendicitis (PA) and to examine geographic patterns of incidence alongside geographic patterns of socioeconomic status. Age- and sex-standardized incidence for AA and PA were determined for each census tract.

The researchers found that during the five-year study period, there were 35,730 patients with AA (including 9,780 cases of PA), of whom 46.4 percent were women. Overall, the median age of the cohort was 29 years. For AA and PA, the statewide incidence was 106 and 29 per 100,000 person-years (PY), respectively. The crude incidence was higher for men and peaked at age 10 to 19 years. The incidence of AA showed significant positive spatial autocorrelation with age and sex standardization, but autocorrelation for PA was half as strong. In hot spots, the median incidence of AA was 118.1 per 100,000 PY versus 86.2 per 100,000 PY among cold spots. Socioeconomic status was higher in cold spots versus hot spots with respect to the mean proportion of college-educated adults and mean per-capita income.

"These findings challenge conventional views that AA occurs randomly and has no predisposing characteristics beyond age/sex," the authors write.