Early thromboprophylaxis does not prevent hospital admissions and death among outpatients with symptomatic COVID-19. Its impact on long-term outcomes, including long-COVID symptoms and performance status, is unknown. We aimed to investigate the long-term effects of thromboprophylaxis given at the time of acute SARS-CoV-2 infection in outpatients.

The OVID trial randomized outpatients older than 50 years with acute COVID-19 to receive either subcutaneous enoxaparin 40 mg once daily for 14 days or standard of care (no thromboprophylaxis). In this follow-up study of the OVID trial, we assessed the 2-year outcomes, including all-cause hospitalization and death, cardiovascular events, long-COVID symptoms, and functional limitations based on the post-COVID-19 functional status scale (PCFS) and EQ-5D5L scale. All patients provided written consent and the study was approved by the ethical commission.

Of 469 potentially eligible patients included in the OVID trial, 468 survived, of whom 439 (mean age: 59 years; 54% men) participated in the post-OVID study. There was no difference in term of hospitalization and death (8.3% in the treatment group vs 10% in controls; RR: 0.83, 95%CI: 0.5-1.5), and of cardiovascular events between groups at two years (Table 1). The risk of presenting with long-COVID symptoms was similar in the two groups (44% in the treatment group vs 47% in the standard of care group), with no difference between groups also concerning individual symptoms. Most common persisting symptoms are showed in Figure 1. A PCFS grade of 1-3, indicating light-to-moderate functional limitation, was recorded in 15% of patients in each group (OR: 0.98, 95% CI: 0.6-1.7). No patients reported severe limitations (PCFS grade 4). Median EQ-VAS score was 85 on 100 points (IQR: 80-90 for the Standard of Care group and 75-90 for the Enoxaparin group).

Early thromboprophylaxis does not improve long-term, two-year clinical and functional outcomes among symptomatic ambulatory patients with acute COVID-19.