Hyperglycaemia at admission may predict COVID-19 outcomes in non-diabetics

In non-diabetic patients with COVID-19, an elevated fasting blood glucose (FBG) level at hospital admission may predict negative outcomes including risk of complications and mortality, a recent study showed.

“This two-centre retrospective study shows, for the first time, that elevated FBG (≥7.0 mmol/L) at admission is independently associated with increased 28-day mortality and percentages of in-hospital complications in COVID-19 patients without previous diagnosis of diabetes,” said the researchers.

The study included 605 consecutive patients (median age 59 years, 46.8 percent female) with COVID-19 and no prior diagnosis of diabetes, with 28-day outcomes and FBG at admission at two hospitals in Wuhan, China, between January 24 and February 10, 2020. Of these, 18.8 percent (n=114) died in hospital within 28 days and 39.2 percent (n=237) developed in-hospital complications. About 34 percent of patients had comorbidities, hypertension being the most common. All enrolled participants had CT-confirmed pneumonia. About 45 percent of patients had FBG >6.1 mmol/L and 29.1 percent had FBG ≥7.0 mmol/L.

FBG ≥7.0 mmol/L at hospital admission was an independent predictor of mortality at 28 days (hazard ratio [HR], 2.30, 95 percent confidence interval [CI], 1.49–3.55; p=0.0002). [Diabetologia 2020;63:2102-2111]

An elevated FBG at admission was also associated with an increased risk of in-hospital complications at 28 days, be it FBG ≥7.0 mmol/L (odds ratio [OR], 3.99, 95 percent CI, 2.71–5.88) or 6.1–6.9 mmol/L (OR, 2.61, 95 percent CI, 1.64–4.41) compared with FBG <6.1 mmol/L.

Other risk factors for 28-day mortality were age (HR, 1.02, 95 percent CI, 1.00–1.04; p=0.0252), male sex (HR, 1.75, 95 percent CI, 1.17–2.60; p=0.0060), and CRB-65 score* 1–2 (moderate pneumonia; HR, 2.68, 95 percent CI, 1.56–4.59; p=0.0003) and 3–4 (severe pneumonia; HR, 5.25, 95 percent CI, 2.05–13.43; p=0.0005). FBG 6.1–6.9 mmol/L at admission also showed a trend toward increased risk of 28-day mortality (HR, 1.71, 95 percent CI, 0.99–2.94; p=0.0524).

The effect of elevated FBG levels on 28-day mortality was consistent regardless of pneumonia severity (CRB-65 score 0 [mild pneumonia]: crude HR, 6.57 and 3.42 for FBG ≥7.0 and 6.1–6.9 mmol/L, respectively, vs FBG <6.1 mmol/L; CRB-65 score >0: crude HR, 1.99 for FBG ≥7.0 mmol/L vs FBG <6.1 mmol/L).

The link between elevated glycaemic levels and COVID-19-related morbidity and mortality has been explored in several studies. [J Diabetes Sci Technol 2020;14:813-821; Lancet Diabetes Endocrinol 2020;8:823-833; Lancet Diabetes Endocrinol 2020;8:813-822; J Clin Virol 2020;127:104354]

However, the effect of FBG level at hospital admission on mortality in patients with COVID-19 without diabetes has not been examined, pointed out the researchers.

“We have … demonstrated that FBG ≥7.0 mmol/L is critical to the prognosis of patients with COVID-19 [and that] the incidence of in-hospital complications increases with the elevation of FBG,” they said.

They noted that the lack of data on HbA_1c may have impacted the findings, as HbA_1c could have established if the elevated FBG levels at admission were due to long-term uncontrolled or stress hyperglycaemia. “However, we believe that acute hyperglycaemia is more important than long-term glycaemic control in predicting the prognosis of hospitalized COVID-19 patients,” they said.

The results suggest that glycaemic testing and control should be carried out for all patients with COVID-19, regardless of their diabetes status. “FBG can facilitate the assessment of prognosis and early intervention of hyperglycaemia to help improve the overall outcomes in the treatment of COVID-19,” they concluded.