Exploring the infectious contribution to intussusception causality using the effects of COVID-19 lockdowns in Australia: An ecological study.

Abstract

Intussusception is the primary cause of acute bowel obstruction in infants. The majority of cases under 2 years of age are classed as idiopathic with viral infection implicated as one of the causes. COVID-19 public health measures led to significant decreases in communicable disease prevalence. During these times, reductions in intussusception frequency were reported - reductions greater than would be expected with our previous understanding of its infectious aetiology. We conducted a retrospective, multi-state, ecological study over a twelve-year period. Monthly case numbers of ICD-10-AM K56.1 'Intussusception' coded admissions were acquired from state-wide admissions datasets from New South Wales (NSW), Victoria and Queensland, representing 77.62% of the eligible Australian population. These counts within differing jurisdictional lockdowns were compared to non-lockdown periods in order to investigate a correlation between intussusception frequency and lockdown periods. We found a negative association between intussusception frequency and lockdown periods in both eligible states. The largest reductions were seen in the under 2 year age groups with Victoria experiencing a 62.7% reduction (Rate ratio (RR) = 0.37, p < 0.0001) and NSW a 40.1% reduction (RR = 0.599, p = 0.006) during lockdown times. Controls for variations in lockdown restrictions between both regional and metropolitan areas also showed expected decreases. Our ecological study demonstrates significant decreases in the frequency of paediatric intussusception admissions during the COVID-19 lockdown periods. The unexpected magnitude of the reductions suggests that the true proportion of infectious disease-caused idiopathic intussusception is greatly underestimated.