COVID-19 and Pre-existing Type 2 Diabetes Mellitus: A Retrospective Observational Study From Eastern India on the Association Between Glycaemic Control and Treatment Outcomes

Background: Diabetes has emerged as an important risk factor for causing severe illness and death from COVID-19. There is a paucity of structured data from the Indian subcontinent on the impact that glycaemic control (both immediate and remote) has on the degree of required medical intervention and mortality among hospitalized COVID-19 patients with type 2 diabetes mellitus (T2DM). Objectives: To evaluate the differences in clinical characteristics and treatment outcomes between well-controlled and poorly controlled patients with T2DM and COVID-19. Methods: This was a retrospective observational study. Data on 177 patients who were hospitalized between February 2021 and July 2021 were categorized into four groups using a cut-off admission plasma glucose of <200 mg/dL and glycated hemoglobin (HbA1c) <7.5%. Results: Patients with poorly controlled diabetes presented at a significantly older age than the other groups. Radiological findings suggested severe lung involvement in them. As a combined group patients with HbA1c ≥7.5% required more ventilatory requirement as compared with the group having HbA1c <7.5% irrespective of admission glucose. They also required prolonged hospitalization and intensive care unit (ICU) stays as compared with the well-controlled diabetes group. In this study, within similar ranges of HbA1c admission glucose seemed to have a numerical impact on mortality without being able to achieve statistical significance. Conclusion: From the current study, it can be concluded that poor glycaemic control, particularly HbA1c ≥7.5%, is an important risk factor for the development of severe COVID-19 and a predictor for the requirement of more intensive treatment and adverse treatment outcomes leading to increased hospital and ICU stay.