Background: The recent outbreak of Coronavirus 2019 (COVID-19) is a respiratory disorder caused by the Acute Respiratory Syndrome Coronavirus 2. At the start of the epidemic, early intubation was the optimal strategy for managing ARDS caused by COVID-19. Several non-invasive methods for respiratory support in patients with moderate to severe COVID-19 may reduce intubation, disease severity, ventilator use, and hospitalization in the intensive care unit (ICU). In this study, the characteristics of COVID-19 patients who failed NIV therapy were compared with those who had successful NIV. 
Materials and Methods: The present descriptive-analytical study was conducted at the COVID-19 center of KHORSHID University Hospital. Patients were aged > 18 years with confirmed COVID-19 and hospitalized in the ICU from the beginning of January to the end of March 2021. They had an oxygen level of < 88% despite receiving 15 L of oxygen with reserve masks and were undergoing non-invasive ventilation (NIV) treatment. Data collection included patients' demographic information, vital signs, and test results upon hospital admission, and assessed disease severity using APACHE, SAPS, and SOFA scores. Patients were categorized into responders (R) and non-responders (NR) to determine predictors of non-invasive ventilation (NIV) success, with follow-up based on device tolerance and changes in vital signs.
Results: 71 Individuals were candidates for NIV. Twenty patients were excluded from the study, and 51 patients were included in the study. Of these, 35 patients underwent NIV treatment failure (NR). On the other hand, 16 (31.4%) patients completely recovered after receiving NIV (R) and they were discharged from the ICU.
Conclusion: Serum Albumin and BMI levels of COVID-19 patients undergoing NIV therapy seem to affect their responses to treatment. Hence, it is recommended to evaluate the nutritional status of patients before the start of NIV.