Healthcare use attributable to COVID-19: a propensity-matched national electronic health records cohort study of 249,390 people in Wales, UK

Journal article

Background: To determine the extent and nature of changes associated with COVID-19 infection in terms of healthcare utilisation, this study observed healthcare contact 1 to 4 and 5 to 24 weeks following a COVID-19 diagnosis compared to propensity-matched controls.Methods: Two hundred forty nine thousand three hundred ninety Welsh individuals with a positive reverse transcription–polymerase chain reaction (RT-PCR) test were identified from data from national PCR test results. After elimination criteria, 98,600 positive individuals were matched to test negative and never tested controls using propensity matching. Cohorts were split on test location. Tests could be taken in either the hospital or community. Controls were those who had tested negative in their respective environments. Survival analysis was utilised for first clinicaloutcomes which are grouped into primary and secondary. Primary outcomes include post-viral-illness and fatigue as an indication of long-COVID. Secondary outcomes include clinical terminology concepts for embolism, respiratory conditions, mental health conditions, ft notes, or hospital attendance. Increased instantaneous risk for positive individuals was quantified using hazard ratios (HR) from Cox regression, while absolute risk (AR) and relative risk were quantified using life table analysis.Results: Analysis was conducted using all individuals and stratified by test location. Cases are compared to controls from the same test location. Fatigue (HR: 1.77, 95% CI: 1.34–2.25, p= <0.001) and embolism (HR: 1.50, 95% CI: 1.15–1.97, p=0.003) were more likely to occur in all positive individuals in the first 4 weeks; however, anxiety and depression (HR: 0.83, 95% CI: 0.73–0.95, p=0.007) were less likely. Positive individuals continued to be more at risk of fatigue(HR: 1.47, 95% CI: 1.24–1.75, p= <0.001) and embolism (HR: 1.51, 95% CI: 1.13–2.02, p=0.005) after 4 weeks. All positive individuals are also at greater risk of post-viral illness (HR: 4.57, 95% CI: 1.77–11.80, p=0.002). Despite statistical association between testing positive and several conditions, life table analysis shows that only a small minority of the studypopulation were affected

Authors: Kennedy, J; Parker, M; Seaborne, M; Mhereeg, M; Walker, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: BioMed Central
• Journal: BMC Medicine
• Volume: 21
• Issue: 1
• Pages: 259-259
• Article number: 259
• Publication date: 2023-07-19
• DOI: 10.1186/s12916-023-02897-5
• EISSN: 1741-7015
• ISSN: 1741-7015
• Language: English
• Keywords: Cohort; Internal medicine; Medicine; Demography; Hazard ratio; Confidence interval; Cohort study; Propensity score matching; Proportional hazards model