Modeling the Recovery of Elective Waiting Lists Following COVID-19: Scenario Projections for England

Abstract

Objectives: A significant indirect impact of COVID-19 has been the increasing elective waiting times observed in many countries. In England's National Health Service, the waiting list has grown from 4.4 million in February 2020 to 5.7 million by August 2021. The objective of this study was to estimate the trajectory of future waiting list size and waiting times up to December 2025.

Methods: A scenario analysis was performed using computer simulation and publicly available data as of November 2021. Future demand assumed a phased return of various proportions (0%, 25%, 50%, and 75%) of the estimated 7.1 million referrals "missed" during the pandemic. Future capacity assumed 90%, 100%, and 110% of that provided in the 12 months immediately before the pandemic.

Results: As a worst-case scenario, the waiting list would reach 13.6 million (95% confidence interval 12.4-15.6 million) by Autumn 2022, if 75% of missed referrals returned and only 90% of prepandemic capacity could be achieved. The proportion of patients waiting under 18 weeks would reduce from 67.6% in August 2021 to 42.2% (37.4%-46.2%) with the number waiting over 52 weeks reaching 1.6 million (0.8-3.1 million) by Summer 2023. At this time, 29.0% (21.3%-36.8%) of patients would be leaving the waiting list before treatment. Waiting lists would remain pressured under even the most optimistic of scenarios considered, with 18-week performance struggling to maintain 60%.

Conclusions: This study reveals the long-term challenge for the National Health Service in recovering elective waiting lists and potential implications for patient outcomes and experience.

Keywords: COVID-19; computer simulation; elective backlog; elective performance; waiting lists; waiting times.

Figure 1

Elective care performance in England’s NHS to August 2021. The dashed gray vertical lines represent the declaration of a pandemic by the World Health Organization on March 11, 2020. NHS indicates National Health Service; RTT, referral-to-treatment.

Figure 2

Model projections (mean and 95% confidence intervals), accounting for the prepandemic referral rate (March 2019-February 2020) with no trend growth and various proportions of the estimated 7.1 m referrals “missed” during the pandemic returning in the 12 months from September 2021. m indicates million; RTT, referral-to-treatment.

Figure 3

Peak mean values of model projections from September 2021 to December 2025, accounting for the prepandemic referral rate (March 2019-February 2020) with no trend growth and various proportions of the estimated 7.1 m referrals “missed” during the pandemic returning in the 12 months from September 2021. m indicates million; Max, maximum; Min, minimum.

Figure 4

Long-term convergence of mean waiting list projections across the considered capacities, accounting for the prepandemic referral rate (March 2019-February 2020) with no trend growth and various proportions of the estimated 7.1 m referrals “missed” during the pandemic returning in the 12 months from September 2021. m indicates million.

Figure 5

Model projections (mean and 95% confidence intervals), accounting for referral growth at the rate observed in the 5 years prepandemic (from March 2015 to February 2020) and various proportions of the estimated 7.1 m referrals “missed” during the pandemic returning in the 12 months from September 2021. m indicates million; RTT, referral-to-treatment.