Abstract: PLOS ONE RESEARCH ARTICLE Lack of efficacy of hydroxychloroquine and azithromycin in patients hospitalized for COVID-19 pneumonia: A retrospective study Anis Saib1, Walid Amara1, Pascal Wang ID2, Simon Cattan1, Azeddine Dellal3, Kais Regaieg4, Stephane Nahon5, Olivier Nallet1, Lee S. Nguyen ID6* a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Cardiology Department, Groupe Hospitalier Intercommunal Le Raincy-Montfermeil, Montfermeil, France, 2 Pneumology Department, Groupe Hospitalier Intercommunal Le Raincy-Montfermeil, Montfermeil, France, 3 Rheumatology Department, Groupe Hospitalier Intercommunal Le Raincy-Montfermeil, Montfermeil, France, 4 Intensive Care Medicine Department, Groupe Hospitalier Intercommunal Le Raincy-Montfermeil, Montfermeil, France, 5 Gastroenterology Department, Groupe Hospitalier Intercommunal Le RaincyMontfermeil, Montfermeil, France, 6 Research & Innovation Department (RICAP), CMC Ambroise Paré, Neuilly-sur-Seine, France * nguyen.lee@icloud.com Abstract Background OPEN ACCESS Citation: Saib A, Amara W, Wang P, Cattan S, Dellal A, Regaieg K, et al. (2021) Lack of efficacy of hydroxychloroquine and azithromycin in patients hospitalized for COVID-19 pneumonia: A retrospective study. PLoS ONE 16(6): e0252388. https://doi.org/10.1371/journal.pone.0252388 Editor: Andrea Cortegiani, University of Palermo, ITALY Received: January 14, 2021 Accepted: May 17, 2021 Published: June 9, 2021 Copyright: © 2021 Saib et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Hydroxychloroquine combined with azithromycin (HCQ/AZI) has initially been used against coronavirus disease-2019 (COVID-19). In this retrospective study, we assessed the clinical effects of HCQ/AZI, with a 28-days follow-up. Methods In a registry-study which included patients hospitalized for COVID-19 between March 15 and April 2, 2020, we compared patients who received HCQ/AZI to those who did not, regarding a composite outcome of mortality and mechanical ventilation with a 28-days follow-up. QT was monitored for patients treated with HCQ/AZI. Were excluded patients in intensive care units, palliative care and ventilated within 24 hours of admission. Three analyses were performed to adjust for selection bias: propensity score matching, multivariable survival, and inverse probability score weighting (IPSW) analyses. Results Overall, 203 patients were included: 60 patients treated by HCQ/AZI and 143 control patients. During the 28-days follow-up, 32 (16.3%) patients presented the primary outcome and 23 (12.3%) patients died. Propensity-score matching identified 52 unique pairs of patients with similar characteristics. In the matched cohort (n = 104), HCQ/AZI was not associated with the primary composite outcome (log-rank p-value = 0.16). In the overall cohort (n = 203), survival and IPSW analyses also found no benefit from HCQ/AZI. In the HCQ/AZI group, 11 (18.3%) patients prolonged QT interval duration, requiring treatment cessation. PLOS ONE | https://doi.org/10.1371/journal.pone.0252388 June 9,..