The meteorological influence on seasonal alterations in the course of acute appendicitis

Background: Several diseases, including acute appendicitis (AA), have been known to undergo seasonal variations. Changes in the incidence and course of AA are attributed to seasonal weather differences, but this connection remains unproven.

Methods: In this retrospective, single-center analysis, we analyzed daily meteorological data over an 8-year period. A connection of day-by-day meteorological data with 680 consecutive appendectomies was performed. Patients' characteristics, intraoperative findings, and outcome parameters were analyzed. Seasons were classified meteorologically as 3-month periods (winter, spring, summer, and autumn).

Results: Nonambient temperature (unusual warm or cold weather) is correlated with a higher rate of complicated (gangrenous or perforated) AA (P = 0.018). In summer and winter, days with nonambient temperatures were more frequent (P < 0.0001). A higher rate of complicated AA was seen during summer and winter (P = 0.009). In addition, patients operated on in summer and accordingly after warm days suffer more complications (P < 0.0001), especially more superficial surgical site infections (P < 0.048).

Conclusions: The concordant observation of more complicated AA and complications after AA with meteorological data and calendric seasonal variations makes it most likely that temperature is a cofactor in complicated AA and contributes to the seasonal variations in AA. Although an increase in the microbiome of the skin during warm seasons might explain the increase in surgical site infection, the functional connection between warmer temperatures and AA complications remains unclear.