Abstract: medRxiv preprint doi: https://doi.org/10.1101/2020.11.25.20234914; this version posted November 30, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 1 The efficacy and safety of hydroxychloroquine in COVID19 patients 2 : a multicenter national retrospective cohort 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Abdulkarim Abdulrahman1,2, Islam AlSayed3, Marwa AlMadhi4 , Jumana AlArayed5, Sara Jaafar Mohammed3, Aesha Khalid Sharif5, Khadija Alansari 3, Abdulla I AlAwadhi 1,6 , Manaf AlQahtani 1,6,7* 1 National Taskforce for Combating the Coronavirus (COVID-19), Bahrain 2 Mohammed Bin Khalifa Cardiac Centre, Bahrain 3 King Hamad University Hospital, Bahrain 4 School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom 5 Ministry of Health, Bahrain 6 Bahrain Defence Force hospital, Bahrain 7 Royal College of Surgeons in Ireland, Bahrain *Corresponding author: Manaf AlQahtani. Email: mqahtani@rcsi-mub.com Phone: +973 39766000 24 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.11.25.20234914; this version posted November 30, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 25 ABSTRACT 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 Background Hydroxychloroquine is an antimalarial drug that received worldwide news and media attention in the treatment of COVID-19 patients. This drug was used based on its antimicrobial and antiviral properties despite lack of definite evidence of clinical efficacy. In this study, we aim to assess the efficacy and safety of using Hydroxychloroquine in treatment of COVID-19 patients who are admitted in acute care hospitals in Bahrain. Methodology We conducted retrospective cohort study on a random sample of admitted COVID19 patients between 24 February and 31 July 2020. The study was conducted in four acute care COVID19 hospitals in Bahrain. Data was extracted from the medical records. The primary endpoint was the requirement of non-invasive ventilation, intubation or death. Secondary endpoint was length of hospitalization for survivors. Three methods of analysis were used to control for confounding factors: logistic multivariate regression, propensity score adjusted regression and matched propensity score analysis. Results A random sample of 1571 patients were included, 440 of which received HCQ (treatment group) and 1131 did not receive it (control group). Our results showed that HCQ did not have a significant effect on primary outcomes due to COVID-19 infection when compared to controls after adjusting for confounders (OR 1.43 95% CI 0.85 to 2.37, P value=0.17). Co-administration of azithromycin had no effect on primary outcomes (OR 2.7 95% CI 0.82 to 8.85 P value =0.10). HCQ was found to be associated with increased risk of hypoglycemia (OR 10.9 95% CI 1.72 - 69.49, P value =0.011) and diarrhea(OR 2.8, 95% CI 1.4-5.5, P value..