Among the 181 patients eligible for analysis, 84 received hydroxychloroquine within 48 hours of admission, eight received hydroxychloroquine more than 48 hours after admission, and 89 did not receive hydroxychloroquine. The median age of patients was 60 years (interquartile range 52-68 years), and 72% were men. Patients in the treatment group had fewer comorbidities, except for liver cirrhosis. The median interval between symptom onset and admission to hospital was 7 days (interquartile range 5-10 days). Overall, initial severity was well balanced between the groups, except for confusion on admission (0 in the treatment group v 6 (7%) in the control group). Azithromycin was administered to 18% of the participants in the treatment group versus 29% in the control group; amoxicillin and clavulanic acid was given to 52% versus 28%, respectively (excluding cointerventions in patients transferred to the intensive care unit.