Association of hyperglycaemia with hospital mortality in nondiabetic COVID-19 patients: A cohort study

Abstract

Objective: Diabetes is a known risk factor for mortality in Coronavirus disease 2019 (COVID-19) patients. Our objective was to identify prevalence of hyperglycaemia in COVID-19 patients with and without prior diabetes and quantify its association with COVID-19 disease course.

Research design and methods: This observational cohort study included all consecutive COVID-19 patients admitted to John H Stroger Jr. Hospital, Chicago, IL from March 15, 2020 to May 3, 2020 and followed till May 15, 2020. The primary outcome was hospital mortality, and the studied predictor was hyperglycaemia [any blood glucose ≥7.78 mmol/L (140 mg/dL) during hospitalization].

Results: Of the 403 COVID-19 patients studied, 51 (12.7%) died; 335 (83.1%) were discharged while 17 (4%) were still in hospital. Hyperglycaemia occurred in 228 (56.6%) patients; 83 of these hyperglycaemic patients (36.4%) had no prior history of diabetes. Compared to the reference group no-diabetes/no-hyperglycaemia patients the no-diabetes/hyperglycaemia patients showed higher mortality [1.8% versus 20.5%, adjusted odds ratio 21.94 (95% confidence interval 4.04-119.0), P < 0.001]; improved prediction of death (P = 0.01) and faster progression to death (P < 0.01). Hyperglycaemia within the first 24 and 48 h was also significantly associated with mortality (odds ratio 2.15 and 3.31, respectively).

Conclusions: Hyperglycaemia without prior diabetes was common (20.6% of hospitalized COVID-19 patients) and was associated with an increased risk of and faster progression to death. Development of hyperglycaemia in COVID-19 patients who do not have diabetes is an early indicator of progressive disease.

Keywords: COVID-19; Diabetes; Hospital mortality; Hyperglycaemia.

Fig. 1

Distribution of study groups and blood glucose measurements in hospitalized COVID-19 patients. (A) The pie chart shows number (%) of patients in the color-coded study groups. These color-codes are consistently used throughout the rest of the paper. DM+/HG+, patients with diabetes and hyperglycaemia; DM+/HG-, patients with diabetes but no hyperglycaemia; DM-/HG+, patients with hyperglycaemia who did not have diabetes; DM-/HG-, patients who had neither diabetes nor hyperglycaemia (B) Funnel plots showing the distribution of patient subsets when considered in all study participants (funnel with white background); in the DM-/HG+ group (yellow background); in the DM+/HG+ group (red background); and in the DM-/HG- group (blue background). N, number of patients; M, number of blood glucose measurements; *, DM+/HG- group (N = 10 (2.5%)).

Fig. 2

Glycemia trends and association of hyperglycaemia with time to death in hospitalized COVID-19 patients. (A) Trends in glycemia over two-weeks following hospital admission for the diabetes- and hyperglycaemia-based, color-coded study groups. N and M indicate number of patients and number of BG measurements, respectively. Shown in the plot for each study group are cubic spline-smoothed, non-linear glycemia trends obtained using generalized estimating equations. Thick lines show point estimates and light-coloured areas show 95% confidence bands. (B) Kaplan-Meier plot for time to death in the color-coded study groups left-censored at the time of first detection of hyperglycaemia. Median time to death is indicated using color-coded numbers and dashed vertical lines. Statistical significance for difference in survival curves was tested using the overall as well as comparison-specific logrank test (indicated at the top-right corner).