The Coronavirus Disease of 2019 (COVID-19) pandemic has caused an international healthcare crisis and produced a large healthcare burden. Diabetes mellitus is a common disease that can be controlled via pharmacologic agents; however, many patients have poor glycemic control, leading to disease-related complications. Diabetes mellitus has been reported in the literature to be associated with increasing morbidity and mortality in COVID-19 patients, and some hypothesize that this is due to insulin dysregulation propagating a pro-inflammatory state. The investigators aim to contribute to the growing body of literature that assesses the associations between glucose homeostasis and COVID-19 disease severity and mortality.

The Coronavirus Disease of 2019 (COVID-19) is caused by an infection from the severe acute respiratory syndrome coronavirus 2, and the first case in the United States was documented on January 31, 2020. Severe acute respiratory syndrome coronavirus 2 is a RNA virus that has 82% homology with severe acute respiratory syndrome coronavirus 2, which caused a pandemic in 2003. Severe acute respiratory syndrome coronavirus 2 enters cells via the angiotensin converting enzyme 2 (ACE2) receptor, which is primarily expressed in the lung. COVID-19 has led to a worldwide pandemic, with over six million deaths attributed to the virus, according to the World Health Organization. This emerging infection has caused an international healthcare crisis with a significant burden on healthcare workers.

Advanced age, male sex, cardiovascular disease, and diabetes mellitus are known to be associated with increasing risk for COVID-19 severity and mortality. Diabetes mellitus is a common disease that affects the general population by disrupting glucose homeostasis. Impaired glycemic control produces a state of hyperglycemia, which leads to multi-organ injury via a chronic, pathophysiologic inflammatory state. Early retrospective studies demonstrated the association of insulin dysregulation with COVID-19 disease severity and mortality. With more data availability and time, many studies have been conducted to better characterize the relationships between hyperglycemia and elevated hemoglobin A1c (HbA1c) with COVID-19 disease susceptibility, severity, and mortality.

Through this retrospective analysis, the investigators investigate the associations of HbA1c levels and hyperglycemia with COVID-19 mortality and disease severity.

Inclusion Criteria:

• At least 18 years of age
• COVID-19 confirmed by laboratory testing (ICD10 U07.1)
• Pneumonia due to COVID-19 (ICD10 J12.82)
• Diagnosis of Diabetes Mellitus

Exclusion Criteria:

• All patients under the age of 18
• COVID in pregnancy

To evaluate diabetes mellitus and the associations with COVID-19 disease severity in patients older than 18 years of age.