Correlation Between HbA1c Levels and Mortality Rates in Hospitalized COVID-19 Patients

Objective Throughout the coronavirus disease 2019 (COVID-19) pandemic, multiple factors have been associated with poor prognosis for those infected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Age, obesity, and medical comorbidities have been linked to poor outcomes, including admission to the intensive care unit (ICU), acute renal failure, stroke, myocardial infarction (MI), mechanical ventilation, and even death for hospitalized COVID-19 patients. Although diabetes mellitus (DM) has also been included in this set of medical comorbidities, there have been inconsistencies in the currently available body of literature, suggesting that mortality rates may or may not be correlated to elevated glycosylated hemoglobin (HbA1c) levels. This study aims to determine whether there is a correlation or trend between a range of HbA1c values and in-hospital mortality among patients admitted to the hospital with a COVID-19 diagnosis. Materials and methods This study was a retrospective review of electronic medical records at Arrowhead Regional Medical Center in Colton, CA. Any patient above the age of 18 admitted to the hospital during a predetermined time frame, with either a positive COVID-19 PCR test on admission or during their hospital stay, was included in the study. These medical charts were reviewed for HbA1c values during admission or within three months prior to admission. In-hospital mortality was then recorded for each medical record with an available HbA1c value. Hospital discharge summaries were used to delineate comorbidities, including chronic kidney disease, cerebrovascular disease, coronary artery disease, congestive heart failure, cancer history, or history of deep vein thrombosis/pulmonary embolism among the patients included in the study. Average HbA1c values were recorded for the mortality and non-mortality groups, and their statistical significance was calculated. Results In this retrospective study, HbA1c levels were compared to mortality rates among adult patients admitted to the hospital with a concurrent COVID-19 diagnosis. From the analysis conducted, those with higher HbA1c levels did not have an increased rate of in-hospital mortality, and those with lower HbA1c levels did not have a decreased rate of in-hospital mortality. Comorbidity data as a confounding factor was also reviewed and excluded from the final analysis. The SARS-CoV-2 vaccine was also excluded as a confounder in this study by selecting a specific time frame for data collection. Based on our results, we propose that HbA1c levels likely have little to minimal correlation with mortality rates among hospitalized COVID-19 patients. Conclusion In this study, we show that HbA1c levels, regardless of concurrent comorbidities, are unlikely to be correlated to mortality rates among hospitalized COVID-19 patients. HbA1c levels should not be used as a marker for whether these patients should be admitted to the hospital for further inpatient management or discharged from the emergency department.