The aim of this study was to compare the outcomes of SARS-CoV-2 RT-PCR-positive and RT-PCR negative Patients in Iran. This cohort study performed on 81393 patients with COVID-19 in six provinces of Iran during 2020. The studied variables include demographic and clinical. To examine the associations between RT-PCR test and death or ICU admission as dependent variable the multiple Bayesian logistic regression model was used by R software. 81393 individual (44.9 % female) with a mean age of 52.98 ± 20.8 years were included to the analysis. At all, 25434 tests (31.2 %) were positive RT-PCR, including 10772 men (44.9%) and 14662 women (55.1%). The multiple Bayesian logistic regression model showed a significant positive association between RT-PCR test results and COVID-19 mortality rate (OR: 1.46; 95% Crl: 1.29- 1.64). Also, males, older age, individual with chronic disease have higher risk of COVID-19 death, however, negative association observed between history of contact and COVID-19 death. We observed a significant inverse association between RT-PCR test results and ICU admission, while, the risk of ICU admission increased significantly by 1.2 times (95% Crl for odds ratio: 1.09, 1.34) among patients with negative RT-PCR test compared to positive RT-PCR test. People with positive RT-PCR test, male gender, older age, having a history of underlying disease have a higher risk of death and hospitalization in the ICU. Therefore, paying attention to these factors will be effective in reducing the risk of death and hospitalization in ICU.