Incidence and Predictors of Clinical Progression in an Early Treated Covid-19 Cohort

ABSTRACT

Background: Early treatment for preventing severe outcome of COVID-19 in high-risk not-hospitalized patients (pts) by monoclonal antibodies or antivirals represented a high-priority approach. Real-world evidence (RWE) from observational studies could give information on clinical effectiveness and predictors of treatment failure. Method(s) Single-center observational study on SARS-CoV-2 pts, not requiring hospital admission but having high-risk of severe outcome from COVID-19. All were selected for early treatment with monoclonal antibodies or antivirals from March 2021 to November 2022. Participants were classified according to whether they were hospitalized due to severe COVID-19 or died by day 30 from starting treatment in the outpatient setting (baseline). We conducted a logistic regression analysis with this binary endpoint and 4 main exposures of interest measured at baseline i) age ( >75 years old) ii) vaccination status iii) VoC, and iv) immunosuppression or having received immunosuppressive therapy. We built a separate model for each of these exposures, which included a specific set of potential confounders. Result(s) 3,491 pts, female 48.6%, median age 67 yrs (IQR 55-77), fully vaccinated 83.7%;previous infection 4.6%;CVD 52.2%;cancer 24.6%;immunodeficiency 40.6%. Prevalence of SARS-CoV-2 VoC delta 8.7%, BA.1 16.9%, BA.2 6.8%, BA.4/5 12.2, BQ 0.1%, other 3.0% (Tab.1A). Treatment exposure was BAM/ETE 569 (16.5%), CAS/IMD 262 (7.6%), SOT 935 (27.1%), TIX/CIL 79 (2.3%), NMV/r 555 (16.1%), MLP 684 (19.8%), RDV 356 (10.3%). Primary endpoint occurred in 80/3,491 pts with a day-30 incident risk of 2.3% (95%CI 1.8-2.9). Tab.1B shows the unadjusted and adjusted odds ratios (OR) of hospitalization due to COVID-19 or death by day 30. After controlling for potential confounders, higher risk was observed for the unvaccinated (OR 1.95;95%CI 1.03-3.71) and for those affected by immunodeficiency [1.73;1.04-2.89). Having delta as reference variant, an increased risk was observed for BA.2 [2.08;1.00-2.34]. No evidence for a difference was seen by age or other comorbidities. Conclusion(s) In this RWE study, largely represented by vaccinated people and prevalently observed in the Omicron era, the estimated risk of clinical failure of early treatment was slightly higher than that recorded in the experimental arms of randomized studies. The analysis confirms that among those eligible for early treatment, the unvaccinated and those with severe immunodeficiency are at higher risk of developing severe COVID-19. Table 1 -A. Main characteristics of 3,491 not-hospitalized people with mildto-moderate COVID-19 at high risk of severe disease observed between March 2021 to November 2022 according to reaching (n=80) or not reaching (3,411) primary clinical endpoint. B. Odds ratios (OR) of having a COVID-19-related hospitalization or death by different exposure factors.