Clinical Features and Changes in Insulin Requirements in People with Type 2 Diabetes Requiring Insulin When Hospitalised with SARS-CoV-2 Infection

Abstract

Background. Uncontrolled hyperglycaemia before and during hospitalisation is a risk factor for adverse outcomes in people with diabetes and SARS-CoV-2 infection. Insulin often at high doses is frequently required to manage hyperglycaemia associated with SARS-CoV-2 infection during hospitalisation. However, there is limited information on the clinical features and sequelae of people with type 2 diabetes (T2DM) not previously on insulin that require insulin as a new treatment when hospitalised with SARS-CoV-2 infection. Aims. To describe the clinical features and insulin treatment sequelae of 113 people with T2DM that required insulin as a new treatment when hospitalised with SARS-CoV-2 infection. Methods. A single-centre study of 113 people with T2DM who were not on insulin before their admission for SARS-CoV-2 infection. The primary aim of our study was to identify clinical and biochemical features that were associated with the need for insulin as a new treatment in people with known T2DM not on insulin treatment at the time of hospitalisation for SARS-CoV-2 infection. We also describe changes in insulin requirements at time of discharge from hospital and 6 weeks later during the first wave of SARS-CoV-2 infection (April–March 2020) in the UK. Clinical, biochemical, and anthropometric data were collected from electronic health records. Results. We observed that of 113 people with T2DM, 35% (n = 39) needed insulin as a new treatment during their hospitalisation for SARS-CoV-2 infection. People requiring insulin were younger, had a higher preadmission HbA1c, were more frequently on oral medication for diabetes before the admission, and were more likely to be obese (body mass index ≥30 kg/m2), with $p$  ≤ 0.001 for all. In multivariable logistic regression analyses, we observed that younger age and higher HbA1c before admission were independently associated with needing insulin, with one-year increase in age associated with decreased odds of needing insulin initiation (OR 0.91, 95% CI 0.83–0.99), and increasing preadmission HbA1c by 1 mmol/mol associated with an increased odds of insulin initiation (OR 1.05, 95% CI 1.002–1.11) ( $p$  < 0.05 for both). Of the 39 people with T2DM who required insulin as a new treatment, 28% remained on insulin at the time of discharge with their insulin dose falling from 1.26 U/kg within the first 7 days of admission to 0.39 U/kg at discharge. At 6 weeks after discharge, 24% of people remained on insulin. Conclusion. More than one-third of people with T2DM not previously treated with insulin required new insulin treatment when hospitalised with SARS-CoV-2 infection, and of this group, 24% remained on insulin at 6 weeks after discharge. This study highlights the important variations of insulin requirements in people with T2DM new to insulin and the importance of a dedicated team for patient education and close follow-up.