Traumatic brain injury during COVID-19 pandemic—time-series analysis of a natural experiment

ObjectivesThis study aims to find if the incidence and pattern of traumatic brain injury (TBI) changed during the COVID-19pandemic. We also aim to build an explanatory model for change in TBI incidence using Google community mobility and alcohol sales data.DesignA retrospective time-series analysis.SettingEmergency department of a tertiary level hospital located in a metropolitan city of southern India. This centre is dedicated to neurological, neurosurgical and psychiatric care.ParticipantsDaily counts of TBI patients seen between 1 December 2019 and 3 January 2021 (400 days); n=8893. To compare the profile of TBI cases seen before and during the pandemic, a subset of these cases seen between 1 December 2019 and 31 July 2020 (244 days), n=5259, are studied in detail.ResultsAn optimal changepoint is detected on 20 March 2020 following which the mean number of TBI cases seen every day has decreased and variance has increased (mean 1=29.4, variance 1=50.1; mean 2=19.5, variance 2=59.7, loglikelihood ratio test: χ2=130, df=1, p