Post-acute health care burden after SARS-CoV-2 infection: A retrospective cohort study of long COVID among 530,892 adults
Authors: McNaughton Candace D. , Austin Peter C. , Sivaswamy Atul , Fang Jiming , Abdel-Qadir Husam , Daneman Nick , Udell Jacob A. , Wodchis Walter , Mostarac Ivona , Atzema Clare L. 
Published: May 2022

AbstractImportanceThe SARS-CoV-2 pandemic portends a significant increase in health care use related to post-acute COVID sequelae, but the magnitude is not known.ObjectiveTo assess the burden of post-acute health care use after a positive versus negative polymerase chain reaction (PCR) test for SARS-CoV-2.Design, Setting, and ParticipantsRetrospective cohort study of community-dwelling adults January 1, 2020 to March 31, 2021 in Ontario, Canada, using linked population-based health data. Follow-up began 56 days after PCR testing.ExposuresIndividuals with a positive SARS-CoV-2 PCR test were matched 1:1 to individuals who tested negative based on hospitalization, test date, public health unit, sex, and a propensity score of socio-demographic and clinical characteristics.Main Outcomes and MeasuresThe health care utilization rate was the number of outpatient clinical encounters, homecare encounters, emergency department visits, days hospitalized, and days in long-term care per person-year. Mean health care utilization for test-positive versus negative individuals was compared using negative binomial regression, and rates at 95th and 99th percentiles were compared. Outcomes were also stratified by sex.ResultsAmong 530,232 unique, matched individuals, mean age was 44 years (sd 17), 51% were female, and 0.6% had received ≥1 COVID-19 vaccine dose. The mean rate of health care utilization was 11% higher in test-positive individuals (RR 1.11, 95% confidence interval [CI] 1.10-1.13). At the 95th percentile, test-positive individuals had 2.1 (95% CI 1.5-2.6) more health care encounters per person-year, and at the 99th percentile 71.9 (95% CI 57.6-83.2) more health care encounters per person-year. At the 95th percentile, test-positive women had 3.8 (95% CI 2.8-4.8) more health care encounters per person-year while there was no difference for men. At the 99th percentile, test-positive women had 76.7 (95% CI 56.3-89.6) more encounters per person-year, compared to 37.6 (95% CI 16.7-64.3) per person-year for men.Conclusions and RelevancePost-acute health care utilization after a positive SARS-CoV-2 PCR test is significantly higher compared to matched test-negative individuals. Given the number of infections worldwide, this translates to a tremendous increase in use of health care resources. Stakeholders can use these findings to prepare for health care demand associated with long COVID.Key PointsQuestionHow does the burden of health care use ≥56 days after a positive SARS-CoV-2 polymerase chain reaction (PCR) test compare to matched individuals who tested negative?FindingsAfter accounting for multiple factors, the mean burden of post-acute health care use was 11% higher among those who tested positive, with higher rates of outpatient encounters, days hospitalized, and days in long-term care. Rates of homecare use were higher for test-positive women but lower for men.For perspective, for every day in January 2022 with 100,000 or more infections, this translates to an estimated 72,000 additional post-acute health care encounters per year for the 1% of people who experienced the most severe complications of SARS-CoV-2; among those in the top 50% of health care use, this translates to 245,000 additional health care encounters per year. This increase will occur in the context of an ongoing pandemic and, in many health care systems, a depleted workforce and backlogs of care. Unless addressed, this increase is likely to exacerbate existing health inequities.MeaningGiven the large number of people infected, stakeholders can use these findings to plan for health care use associated with long COVID.