Outcomes of Hydroxychloroquine Usage in United States Veterans Hospitalized with COVID-19

Background: Despite limited and conflicting evidence, hydroxychloroquine, alone or in combination with azithromycin, is widely used in COVID-19 therapy. Methods: We performed a retrospective study of electronic health records of patients hospitalized with confirmed SARS-CoV-2 infection in US Veterans Health Administration medical centers between March 9, 2020 and April 29, 2020. Patients hospitalized within 24 h of diagnosis were classified based on their exposure to hydroxychloroquine alone (HC) or with azithromycin (HC+AZ) or no HC as treatments. The primary outcomes were mortality and use of mechanical ventilation. Findings: A total of 807 patients were evaluated. Compared to the no HC group, after propensity score adjustment for clinical characteristics, the risk of death from any cause was higher in the HC group (adjusted hazard ratio [aHR], 1.83; 95% confidence interval [CI], 1.16-2.89; p = 0.009), but not in the HC+AZ group (aHR, 1.31; 95% CI, 0.80-2.15; p = 0.28). Both the propensity-score-adjusted risks of mechanical ventilation and death after mechanical ventilation were not significantly different in the HC group (aHR, 1.19; 95% CI, 0.78-1.82; p = 0.42 and aHR, 2.11; 95% CI, 0.96-4.62; p = 0.06, respectively) or in the HC+AZ group (aHR, 1.09; 95% CI, 0.72-1.66; p = 0.69 and aHR, 1.25; 95% CI, 0.59-2.68; p = 0.56, respectively) compared to the no HC group. Conclusions: Among patients hospitalized with COVID-19, this retrospective study did not identify any significant reduction in mortality or in the need for mechanical ventilation with hydroxychloroquine treatment with or without azithromycin.