Senior Researcher in Pharmacoepidemiology University of Oxford Oxford, United Kingdom
Background: Acute morbidity and mortality associated with SARS-CoV-2 infection (COVID-19) is well described, but there is growing recognition that COVID-19 can also have post-acute health outcomes. Most evidence to date focuses on ongoing self-reported symptoms of COVID-19 or lacks an adequate control group.
Objectives: To build a passive surveillance system comprising linked national level real-world data will be used to assess post-acute COVID-19 outcomes in England, measuring healthcare use, morbidity and mortality in the post-acute phase of COVID-19 (28 days after test). We report preliminary findings on all-cause and cause-specific mortality in COVID-19 positives vs negatives 3, 6 and 12 months after index date.
Methods: We linked COVID-19 test data for all ages from March 2020 to April 2022 to vaccine registry, healthcare records, and national death records. Positive and negative COVID-19 tests were matched on week of test, sex, 5-year age band, index of multiple deprivation and geographical area of residence using a 1:1 ratio. Index date was defined as earliest SARS-CoV-2 test. All individuals were censored at the end of follow up period and at outcome occurrence, negatives were additionally censored when they if they tested positive. Here, we report preliminary findings on all-cause and cause-specific mortality risk in COVID-19 positives vs negatives at 3, 6 and 12 months after index date.
Results: After linkage and matching, the cohort comprised 6,774,662 positives and 6,774,662 negatives. Overall post-acute all-cause mortality rates among positives was 1,112 per 100,000 population at 3 months post infection (1,107 at 6 months and 140 at 1 year). Rates were higher in positives compared to negatives (Risk Ratio (RR) 1.74, 1.77, 1,82, respectively). Notable increased risk of death in positives at 3, 6 and 12 months was seen where Mental, Behavioural and Neurodevelopmental disorders (RR: 3.65, 3.71, 3.68, respectively) and Nervous system diseases (RR: 2.88, 2.91, 2.93, respectfully) were the primary causes of death.
Conclusions: Here, we report increased overall mortality up to one year after infection, with elevated risk for specific causes of death. Future analyses will incorporate adjustment for confounders which could alter these results, such as previous co-morbidities. This national surveillance system will allow for the identification of widespread and rare outcomes and predictors of outcomes among those with milder COVID-19 illness, investigation of the burden of long-term sequelae from the COVID-19 pandemic and help inform planning and provision of healthcare services.
