Is there seasonal variation in gallstone related admissions in England? a retrospective cohort study of 396 879 admissions

Purpose: Gallstone related pathology (GRP) accounts for a significant proportion of general surgery admissions. The aim of this study is to investigate if seasonal variation for GRP admissions exist in England allowing improved resource allocation and planning. No other study has addressed this. Methods: This multicentre retrospective cohort study included only emergency adult (≥18 years old) admissions to acute secondary care with ICD-10 codes associated with gallstones between 01/01/2010 to 31/12/2019 in England using Hospital Episode Statistics data. Seasons were defined according to United Kingdom Met Office. Results: A total of 396 879 GRP related admissions were recorded during the specified period, accounting for 1.44% of all emergency admissions. Cholecystitis accounted for 49.1% (n=195 058) of admissions. The modal age of admission was 75 - 84 years old. There was a progressive increase in the number of admissions throughout the data collection period. Our study suggests a significant seasonal peak in Summer (n=102 620) based cumulative admissions per season and a linear regression model (p<0.001), followed by Autumn (n=102 267), then Spring (n=97 807) and finally Winter (n=94 185). When considering GRP admissions as a proportion of all emergency admissions, Autumn and then Summer see the highest proportions at 1.47% (102 267/6 961 395) and 1.46% (102 620/7 011 001) respectively which are significant when compared to the lower Spring, 1.42% (97 807/6 904 013) and Winter, 1.40% (94 185/6 742 228) months using X2 (p<0.05). This is clearly depicted in Figure 1. Spectral analysis confirmed there is seasonality in the emergency GRP admissions every 12 months. A forecasting model was shown to be reliable;all observed admissions for 2019 were within the 95% prediction intervals for each month for the proportion of emergency GRP admissions. Discussion: Resource allocation towards the Summer and Autumn months to target seasonal peaks in GRP should be considered. Given the steady rise in GRP admissions with the added strain of COVID-19 delaying elective operations perhaps there needs to be greater emphasis on resource allocation towards public health campaigns for gallstone disease, whilst training and hiring more doctors who can treat GRP. This includes surgeons, endoscopists and radiologists. This will allow safe and timely intervention for patients vulnerable to the risks that GRP can pose, particularly in the elderly. [Formula presented]