Clinical Outcomes of Outpatients With Suspected Covid-19 Treated With Chloroquine Compounds in Brazil: A Nationwide Telemedicine Study

ABSTRACT

Introduction: Following the inception of the COVID-19 pandemic, chloroquine compounds were proposed as potential therapeutic strategies, at the cost of a potential increase in cardiovascular risk. We aimed to evaluate clinical outcomes of patients with COVID-19, comparing those using chloroquine compounds to individuals without specific treatment. Method(s) Outpatients with suspected COVID-19 in Brazil who had at least 1 ECG transmitted to a Telehealth Network, were prospectively enrolled in 2 arms (G1 treatment with chloroquine compounds and G2 without specific treatment) and G3 registry of other specific treatments. Outcomes were assessed through follow-up phone calls on days 3 and 14, and also administratively collected from national mortality and hospitalization databases. The primary outcome was composed of hospitalization and all-cause death. The association between treatment groups and the primary outcome was evaluated by logistic regression. Significant variables (p<0.10) were included in 4 multivariate models 1 unadjusted;2 adjusted for age and sex;3 adjusted for model 2 plus cardiovascular risk factors and 4 adjusted for model 3 plus COVID-19 symptoms (when available from phone contact). Result(s) In 303 days, 712 (10.2%) patients were allocated in G1 (chloroquine), 3623 (52.1%) in G2 (control) and 2622 (37.7%) in G3 (other treatments). Median age was 49 (IQR 38 - 62) years, 57% women. Of these, 1969 had successful phone contacts (G1 260;G2 871;G3 838). The primary outcome was more frequent in groups 1 and 3 compared to the control group, when assessed exclusively by phone (G1 38,5% vs. G2 18,0% vs. G3 34,2%, p<0,001) or combined with administrative data (G1 19,5% vs. G2 11,0% vs. G3 18,2%, p<0,001). In the adjusted models, chloroquine independently associated with a greater chance of the primary outcome: phone contact (model 4) OR=3.24 (95% CI 2.31 - 4.54), p<0.001;phone + administrative data (model 3) OR=1.99 (95% CI 1.61 - 2.44), p<0.001. Chloroquine also independently associated with higher mortality, as assessed by phone + administrative data (model 3) OR=1.67 (95% CI 1.20 - 2.28). Conclusion(s) Chloroquine compounds associated with a higher risk of poor outcomes in outpatients with COVID-19 compared to standard care.