A prospective study of the impact of glycaemic status on clinical outcomes and anti-SARS-CoV-2 antibody responses among patients with predominantly non-severe COVID-19.

Aims: We carried out this prospective study of predominantly non-severe COVID-19 patients, to evaluate the influence of glycaemic status on clinical outcomes and neutralising antibody (Nab) responses, potentially relevant to the COVID-19 vaccination programme.

Methods: We included consecutive adults admitted to Queen Mary Hospital for COVID-19 from July 2020-May 2021. Glycaemic status was defined by admission HbA1c. Clinical deterioration was defined by radiological progression/new oxygen requirement/intensive care requirement/death. COVID-19 survivors had Nab measurements at 1-month, 2-month, 3-month and 6-month post-discharge.

Results: Among 605 patients (96.9% non-severe COVID-19; 325 normoglycaemia, 185 prediabetes, 95 diabetes), 74 (12.2%) had clinical deterioration, more likely with worse glycaemic status and higher HbA1c (p < 0.001). Older age (p < 0.001), higher viral loads (p < 0.001), higher C-reactive protein (CRP) (p < 0.001) and symptomatic presentation (p = 0.008), but not glycaemic status/HbA1c, independently predicted clinical deterioration. Older age (p = 0.001), higher CRP (p = 0.038), elevated lactate dehydrogenase (p = 0.046) and interferon treatment (p = 0.001), but not glycaemic status/HbA1c, independently predicted Nab titres. Rate of Nab titre decline was comparable across glycaemic status.

Conclusions: COVID-19 patients with worse glycaemic status were more likely to deteriorate clinically, mediated through the association of worse glycaemic status with older age, more severe inflammation and higher viral loads. Importantly, Nab responses did not differ across glycaemic status.