Glucose concentration predicting mortality in patients with COVID-19: A propensity score-matched study

Patients with coronavirus disease-19 (COVID-19) often develop systemic inflammation, which is associated with increased mortality. Elevated blood glucose levels can exacerbate the cytokine storm, further worsening disease severity and accelerating patient death. Therefore, this study aims to investigate the association between glucose levels and mortality in hospitalized patients, providing insights into the importance of optimizing glucose management in hospitalized COVID-19 patients.

A retrospective cohort study was conducted, involving adult COVID-19 patients in a university hospital. The primary outcome was in-hospital mortality. Propensity score matching (PSM) was utilized to match patients' baseline characteristics. Discrimination capacity of different models was assessed using C-statistics, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Trends in blood glucose over time were detected using the ordinary least squares model.

Among the 4583 COVID-19 patients during the study period, 2147 (46.8 %) exhibited normal glycemia, while 2436 (53.2 %) had admission hyperglycemia. After adjusting for confounding factors through multivariate regression analysis, patients with hyperglycemia showed significantly higher odds of in-hospital mortality (adjusted odds ratio [aOR]: 3.10, 95 % CI: 2.25 to 4.28; P < 0.001). PSM analysis yielded similar results (aOR: 2.66, 95 % CI: 2.09 to 3.41; P < 0.001). The incorporation of admission glucose significantly improved C-statistics (P < 0.001), IDI (P < 0.001), and NRI (P < 0.001) for predicting mortality.

This study concludes that blood glucose levels ≥ 6.1 mmol/L can independently predict all-cause mortality and clinical sequelae in COVID-19 patients. Furthermore, even a mild increase in blood glucose was associated with a significantly higher risk of mortality in these patients. These findings underscore the importance of managing hyperglycemia and monitoring blood glucose in individuals with COVID-19.