Patients without known diabetes found to have high random blood glucose levels in the emergency department are at higher risk of mortality and cardiovascular events compared to patients who had normal blood glucose levels, according to a study from Sweden published in the journal Cardiovascular Diabetology.¹

Researchers conducted a retrospective cohort study of 618,694 patients, mean age 48 years, visiting the emergency department (ED) at any one of seven hospitals in the cities of Stockholm and Gothenburg from 2006-2016. The patients were categorized into four groups as per the random blood glucose level at the time of admission: hypoglycemia (< 3.9 mmol/L [70.2 mg/dL]), normal glucose tolerance (NGT) (3.9-7.8 mmol/L [70.2-140.4 mg/dL]), dysglycemia (7.8-11.1 mmol/L [140.4-199.8 mg/dL]) and hyperglycemia (>11.1 mmol/L [199.8 mg/dL]). None of the study participants had a prior history of diabetes. The objective of the study was to determine if blood glucose at admission correlated with risk of all-cause and cardiovascular mortality and CV events (myocardial infarction, stroke and heart failure).

At the time of their hospitalization, 0.3% patients were hypoglycemic, 85% had normal glucose tolerance, 13% had dysglycemia while 2% patients had hyperglycemia. Over a mean follow-up time of 3.9 years, there were 44,532 (7.2%) deaths. Of these, 11.5% had hypoglycemia, 6% had normal glucose tolerance, 12.7% had dysglycemia and 20.6% patients had hyperglycemia.

Patients with hypoglycemia had the highest risk of all-cause mortality with hazard ratio of 2.58.  after adjusting for multiple factors. Mortality was also found to be higher among patients with hyperglycemia (HR 1.69) and dysglycemia (HR 1.16) compared to patients with NGT.

Assessment of the risk of cardiovascular outcomes, the secondary outcomes of the study, showed that hyperglycemic patients were twice more likely to experience CV events vis-à-vis patients with NGT. The HRs for myocardial infarction, stroke and heart failure in the hyperglycemic patients were 2.28, 1.62 and 1.60, respectively.

This study involving more than 600,000 patients without known diabetes has demonstrated the greater risk of mortality and CV events among patients with admission hyperglycemia and hypoglycemia compared to the normoglycemic patients. “The higher the random blood glucose level at admission, the greater was the risk of these events, both at early and at long-term follow-up”.  This suggests that doing a random blood glucose in the ED, which is an inexpensive and readily available test, can help to identify at-risk patients. The cut-off was an admission blood glucose level ≥140.4 mg/dL with the risk further increasing if the blood glucose level was nearly 200 mg/dL or higher. However, this being an observational study, no causal association between raised blood glucose levels and mortality and CV events can be established.

Reference

1. Catarina Djupsjö, et al. Admission glucose as a prognostic marker for all-cause mortality and cardiovascular disease. Cardiovasc Diabetol. 2022 Nov 26;21(1):258. doi: 10.1186/s12933-022-01699-y.