dcyphr | Association of Treatment With Hydroxychloroquine or Azithromycin With In-Hospital Mortality in Patients With COVID-19 in New York State


This was a retrospective study about the effect of hydroxychloroquine (with or without azithromycin) on in-hospital mortality and abnormal electrocardiogram findings. The study focused on adverse effects of this drug, opposed to its efficacy as a COVID-19 therapeutic. Records from 25 NY metropolitan region hospitals (representing 88.2% of COVID-19 patients in the area) were collected. Four groups were examined: patients receiving hydroxychloroquine and azithromycin, hydroxychloroquine alone, azithromycin alone, and neither drug.


As COVID-19 vaccines are still in development and testing phases, many healthcare professionals are experimenting with therapeutic agents as immediate treatment. Hydroxychloroquine (often in combination with azithromycin) has become a top candidate amongst these agents. Despite its popularity, few studies about the drug’s adverse effects have been conducted. This study aims to understand hydroxychloroquine and azithromycin prescription patterns, as well as their connection to in-hospital mortality and cardiac abnormalities (such as arrhythmia or QT prolongation).


The medical records of 1438 lab verified COVID-19 patients (59.7%% male, median age 63) from 25 hospitals were collected and analyzed. A two week sampling period was used to ensure complete complete discharge and sufficient patient follow up. 51.1% of patients received both hydroxychloroquine and azithromycin, 18.8% received only hydroxychloroquine, 14.7% received azithromycin alone and 15.4% received neither medication. Patient demographics, vital signs, and lab results were collected within 24 hours of hospitalization and for the duration of their hospital stay.


Based on chest imaging, O2 saturation measurements, AST, alanine, and aminotransferase tests, patients in the hydroxychloroquine with azithromycin group generally presented more severe illness. 95% of hydroxychloroquine with azithromycin presented abnormal initial chest imaging results (such as air space opacity, lung infiltrate, and pneumonia).

Patients receiving both hydroxychloroquine with azithromycin had higher levels of ICU admission versus those on hydroxychloroquine alone or azithromycin alone (30.7% vs 19.2% vs 10.9% respectively). Hydroxychloroquine with azithromycin patients were also more likely to need mechanical ventilation.

Adjusted results for in-hospital mortality showed no significant difference between any of the groups. Estimated mortality during the trial window was: 22.5% for hydroxychloroquine with azithromycin, 18.9% for hydroxychloroquine alone, 10.9% for azithromycin alone, and 17.8% for neither drug.

Between all groups, arrhythmia and other abnormal electrocardiogram results were the most commonly reported adverse effects. Patients taking hydroxychloroquine in combination with azithromycin were more likely to experience such cardiac problems. Cardiac arrest was also more common in patients receiving both medications. 27.1% of patients receiving both medications together exhibited abnormal ekg findings and 15.5% experienced cardiac arrest (vs 14.0% and 6.8% respectively in the control group).


Results of this study suggest that hydroxychloroquine (with or without azithromycin) does not result in significantly increased in-hospital mortality. Patients receiving hydroxychloroquine combined with azithromycin were, however, more likely to experience cardiac arrest, arrhythmia, or other cardiac abnormalities. This statistic could, however, be affected by increased medical attention (more frequent screening) as patients taking both drugs generally exhibited more severe illness.