ABSTRACT
Background: Venous thromboembolism has been reported in patients with coronavirus disease 2019 (COVID-19). It remains unclear if premorbid use of prophylactic oral anticoagulation, for reasons other than COVID-19, protects against death in patients with COVID-19. The aim of this study was to estimate if the risk of all-cause mortality, hospital admission or intensive care unit (ICU) admission for individuals with verified SARS-CoV-2 was lower if patients used oral anticoagulant (OAC) therapy prior to a positive COVID-19 status. Methods: Data were obtained using national health registries. Cohort entry was the day of a positive SARS-CoV-2 test, and individuals were followed for 14â days or until death or hospital admission. Adjusted Cox proportional hazard regressions and competing risk analyses were used to estimate the risk of all-cause mortality, hospital admission and ICU admission in OAC users compared with patients with no use of OAC. Results: In this nationwide cohort study a total of 244 522 individuals were included (median age 35â years (interquartile range 21-52); 124 095 (51%) female), among whom 3710 (1.5%) were OAC users. In the adjusted Cox regression cohort, there was no difference in risk of all-cause mortality in OAC versus non-OAC users. (hazard ratio (HR) 1.13, 95% CI 0.99-1.30). Hospital admission risk (HR 1.11, 95% CI 1.02-1.20) was slightly increased in OAC users, and there was no difference between the groups regarding the risk of ICU admission (HR 0.96, 95% CI 0.74-1.24). Conclusions: In individuals with confirmed SARS-CoV-2, pre-existing treatment with OAC was not associated with prophylactic benefits in the prevention of hospital admission, ICU admissions or death. Prescription patterns should remain unchanged.
ABSTRACT
OBJECTIVE: Hydroxychloroquine has been proposed as a primary prophylactic agent against coronavirus disease 2019 (COVID-19). This study aimed to investigate if patients treated with hydroxychloroquine for a non-COVID-19 indication had a lower risk of verified infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) compared with matched controls. METHODS: A cohort comprising all persons in Denmark collecting hydroxychloroquine prescriptions in 2020 and 2019 (i.e., both during and before SARS-CoV-2 was confirmed in Denmark), matched by age and sex with controls, was studied. Data were collected using the Danish national registries, which contain complete information on patient health data, prescriptions and microbiological test results. The main outcome was microbiologically verified SARS-CoV-2 infection. RESULTS: In total, 5488 hydroxychloroquine users were matched with 54,486 non-users. At baseline, the groups differed in terms of diagnoses of pulmonary disease, cardiovascular disease, renal disease, gastrointestinal/metabolic disease and dementia, as well as treatment with antirheumatic drugs. The final model was adjusted for these potential confounders. Use of hydroxychloroquine for non-COVID-19 indications was not associated with any change in confirmed SARS-CoV-2 (hazard ratio 0.90, 95% confidence interval 0.76-1.07). This result was robust in the propensity-score-matched sensitivity analysis. CONCLUSION: This study, which is the largest to date to investigate the primary prophylactic effect of hydroxychloroquine against SARS-CoV-2, does not support any prophylactic benefit of hydroxychloroquine in the prevention of infection with SARS-CoV-2.