Magagnoli (2020)
Outcomes of Hydroxychloroquine Usage in United States Veterans Hospitalized with COVID-19
Treatment for COVID-19 (Treated with hydroxychloroquine + azithromycin vs. Not received)
COVID-19 (death)
Hazard ratio: 1.250 (0.590-2.680) Adjusted model


Retrospective observational study

Medical records


This national retrospective cohort study evaluated information on hospitalized patients with confirmed SARS-CoV-2 infection using data from the Department of Veterans Affairs (VA). During the study period, 807 hospitalized patients with laboratory-confirmed COVID-19 who met the inclusion criteria were included in the study.

The median ages in years (range) were 71 (27–99), 68 (28–95), and 70 (22–99) in the hydroxychloroquine (HC), HC with azithromycin (HC+AZ), and the no HC groups, respectively. In this cohort of 807 patients, 121 (15%) and 67 (8.3%) patients were taking angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, respectively. Among the 807 patients, 198 (24.5%) and 214 (26.5%) patients were treated with HC and HC+AZ, respectively, although 395 (49.0%) patients did not receive HC at any time during their hospitalization. Among the 412 (51.1%) patients who received HC, 355 (86.2%) patients were started on HC treatment before the institution of mechanical ventilation. The median daily doses (interquartile range [IQR]) of HC were 400 (400–480) mg and 422.2 (400–480) mg in the HC and HC+AZ groups, respectively. The median (IQR) durations of treatment with HC were 5 (3–5) days and 5 (4–6) days in the HC and HC+AZ groups, respectively. Of these 807 patients, 124 (15.4%) died, 517 (64.1%) were discharged alive, and 166 (20.6%) remained hospitalized at the end of the study period. The unadjusted mortality rates were 19.2%, 22.9%, and 9.4% in the HC, HC+AZ, and no HC groups, respectively (p < 0.001), in patients who were treated with HC at any time during the hospitalization period.


52 Day

COVID-19 (death)


Death after Mechanical Ventilation (Mechanical ventilation includes both non-invasive and invasive mechanical ventilation)


Treatment for COVID-19

HC Treatment Initiated after Mechanical Ventilation. Among patients who underwent mechanical ventilation and did not receive HC treatment before ventilation, the unadjusted mortality rates were 58.6%, 60.7%, and 33.3% in the HC, HC+AZ, and no HC groups.

Not received

Treated with hydroxychloroquine + azithromycin

Hazard ratio

1.250 (0.590-2.680)




COVID-19-relevant clinical and demographic characteristics, hydroxychloroquine use, with or without azithromycin

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.