The COVID-19 pandemic has led to a substantial reduction in gastrointestinal endoscopies, creating a backlog of procedures. We aimed to quantify this backlog nationally for England and assess how various interventions might mitigate the backlog.

We did a national analysis of data for colonoscopies, flexible sigmoidoscopies, and gastroscopies from National Health Service (NHS) trusts in NHS England's Monthly Diagnostic Waiting Times and Activity dataset. Trusts were excluded if monthly data were incomplete. To estimate the potential backlog, we used linear logistic regression to project the cumulative deficit between actual procedures performed and expected procedures, based on historical pre-pandemic trends. We then made further estimations of the change to the backlog under three scenarios: recovery to a set level of capacity, ranging from 90% to 130%; further disruption to activity (eg, second pandemic wave); or introduction of faecal immunochemical testing (FIT) triaging.

We included data from Jan 1, 2018, to Oct 31, 2020, from 125 NHS trusts. 10 476 endoscopy procedures were done in April, 2020, representing 9·5% of those done in April, 2019 (n=110 584), before recovering to 105 716 by October, 2020 (84·5% of those done in October, 2019 [n=125 072]). Recovering to 100% capacity on the current trajectory would lead to a projected backlog of 162 735 (95% CI 143 775–181 695) colonoscopies, 119 025 (107 398–130 651) flexible sigmoidoscopies, and 194 087 (172 564–215 611) gastroscopies in January, 2021, attributable to the pandemic. Increasing capacity to 130% would still take up to June, 2022, to eliminate the backlog. A further 2-month interruption would add an extra 15·4%, a 4-month interruption would add an extra 43·8%, and a 6-month interruption would add an extra 82·5% to the potential backlog. FIT triaging of cases that are found to have greater than 10 μg haemoglobin per g would reduce colonoscopy referrals to around 75% of usual levels, with the backlog cleared in early 2022.

Our work highlights the impact of the pandemic on endoscopy services nationally. Even with mitigation measures, it could take much longer than a year to eliminate the pandemic-related backlog. Urgent action is required by key stakeholders (ie, individual NHS trusts, Clinical Commissioning Groups, British Society of Gastroenterology, and NHS England) to tackle the backlog and prevent delays to patient management.