Seasonal Variation in Acute Cholecystitis: An Analysis of Cholecystectomies Spanning Three Decades.

BACKGROUND

Seasonal variation in the occurrence of medical illnesses reflects the effect of the environment, provides insight into pathogenesis, and can assist health care administrators in allocating resources accordingly. Seasonal variation has been reported in various infectious and surgical diseases, but has been rarely studied in acute cholecystitis. Our objective was to study seasonal variation in acute cholecystitis at our institution.

METHODS

We performed a retrospective analysis of patients who underwent cholecystectomy for acute cholecystitis from January 1988 to December 2018. Chi-square goodness-of-fit test was used to analyze seasonality of acute cholecystitis adjusting for variation in number of days between seasons. The number of days for seasons were taken as 92, 92, 91, and 90.25 for spring, summer, fall, and winter, respectively.

RESULTS

Overall, 3924 patients underwent cholecystectomy for acute cholecystitis during the study period. The frequency of cholecystectomies performed varied between months (minimum February n = 259, maximum July n = 372, P < 0.001) and seasons (minimum winter n = 789, maximum summer n = 1101 P < 0.001). Age and gender distribution across months and seasons was similar (P > 0.05).

CONCLUSIONS

Our findings confirm seasonal variation in occurrence of acute cholecystitis with summer season witnessing the most and the winter season encountering the least patients with acute cholecystitis. Validation of our findings through prospectively collected data at national level is the way forward.