en COVID 19 Original Research Original Research <strong>Background: </strong>This study aims to provide information on the success rate of CPR in COVID-19 patients and some probable risk factors of mortality in these cases.<br> &nbsp;&nbsp; <strong>Methods:</strong> In this historical cohort design, the CPR success rate probable risk factors of 737 critically ill patients during the COVID-19 pandemic in 17 hospitals in the catchment area of Iran University of Medical Sciences, Tehran, Iran, was evaluated between Feb and Apr 2020. Data were extracted from a database that is a part of a national integrated care electronic health record system and analyzed with logistic and Cox regression models.<br> &nbsp;&nbsp; <strong>Results:</strong> COVID-19 cases were 341 (46.3%). The mean age in COVID-19 cases and non-COVID-19 patients were 70.0&plusmn;14.6 and 63.0&plusmn;19.3 years, respectively (P<0.001). The mortality was significantly higher in COVID-19 patients (99.1% vs. 74%, OR: 39.6, 95%CI: 12.4, 126.2). Cardiovascular diseases were the most frequent underlying disease (46.3% of COVID-19 cases and 35.1% of non-COVID-19 patients). Being a COVID-19 case (OR: 29.0, 95%CI: 8.9, 93.2), Intensive care unit admission (OR: 2.6, 95%CI: 1.5, 4.6) and age for each ten-year increase (OR: 1.2, 95%CI: 1.1, 1.4) were observed to be independent risk factors of mortality following CPR. The hazard ratio of being a COVID-19 patient was HR= 1.8 (95%CI: 1.5, 2.1).<br> &nbsp;&nbsp; <strong>Conclusion:</strong> Critically ill COVID-19 patients who undergo CPR have a decreased chance of survival in comparison to non-COVID-19 patients. Severe Acute Respiratory Syndrome Coronavirus 2, COVID-19, Cardiopulmonary Resuscitation, Mortality, Risk Factors 338 344 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-7067-2&slc_lang=en&sid=1 Behrooz Banivaheb b.banivaheb@gmail.com 200319475328460069461 200319475328460069461 No Minimally Invasive Surgery Research Centre, Iran University of Medical Sciences, Tehran, Iran Parmida Shahbazi parmida.shabazi@gmail.com 200319475328460069462 200319475328460069462 No Minimally Invasive Surgery Research Centre, Iran University of Medical Sciences, Tehran, Iran Nima Hemmati dr.nima.hemmati@gmail.com 200319475328460069463 200319475328460069463 No Minimally Invasive Surgery Research Centre, Iran University of Medical Sciences, Tehran, Iran Ashkan Yahyavi ashkan.yahyavi@Gmail.com 200319475328460069464 200319475328460069464 No Research Center for Prevention of Cardiovascular Disease, Iran University of Medical Sciences, Tehran, Iran Pegah Derakhshan pegah.derakhshan1997@gmail.com 200319475328460069465 200319475328460069465 No Minimally Invasive Surgery Research Centre, Iran University of Medical Sciences, Tehran, Iran Seyed Mohammad Tabatabaei Jabali mtjabali@gmail.com 200319475328460069466 200319475328460069466 No Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iran Ali Kabir kabir.a@iumc.ac.ir 200319475328460069467 200319475328460069467 Yes Minimally Invasive Surgery Research Centre, Iran University of Medical Sciences, Tehran, Iran