In a propensity score-matched analysis of COVID-19 patients, 190 individuals treated with hydroxychloroquine were exactly matched with 190 untreated patients. The analysis demonstrated:

• A 51% decrease in the mortality hazard ratio for the hydroxychloroquine group based on Cox regression ($p = 0.009$).
• Significantly improved survival in the hydroxychloroquine group as shown by Kaplan–Meier survival curves, with enhanced survival persisting up to 28 days from admission.