Diabetes Q&A

Study Supports Lower Cut-Off Point for Prediabetes

Prediabetes is associated with an increased risk of cardiovascular disease (CVD), even in patients with fasting glucose concentrations as low as 5.6 mmol/L or HbA1c of 39 mmol/mol, according to a recent meta-analysis.

The cutoff point between prediabetes—defined as an intermediate state between normoglycemia and diabetes—and diabetes remains controversial. In order to further evaluate the link between various definitions of prediabetes and the risk of CVD, researchers conducted a meta-analysis of prospective cohort studies reporting on this association.
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Prediabetes was defined as impaired fasting glucose according to the criteria of the American Diabetes Association (ADA) (fasting glucose 5.6-6.9 mmol/L), the WHO expert group (fasting glucose 6.1-6.9 mmol/L), impaired glucose tolerance (2 hour plasma glucose concentration 7.8-11.0 mmol/L during an oral glucose tolerance test), or raised hemoglobin A1c (HbA1c) of 39-47 mmol/mol(5.7-6.4%) according to ADA criteria or 42-47 mmol/mol (6.0-6.4%) according to the National Institute for Health and Care Excellence (NICE) guideline.

Compared with normoglycemia, prediabetes (according to ADA or WHO criteria) was associated with an increased risk of composite cardiovascular disease, coronary heart disease, stroke, and all-cause mortality. Increases in HbA1c to 39-47 mmol/mol or 42-47 mmol/mol were associated with increased risk of composite CVD and coronary heart disease, but not with increased risk of stroke or all-cause mortality.

“Prediabetes, defined as impaired glucose tolerance, impaired fasting glucose, or raised HbA1c, was associated with an increased risk of cardiovascular disease,” the researchers concluded.  “The health risk might be increased in people with a fasting glucose concentration as low as 5.6 mmol/L or HbA1c of 39 mmol/mol.”

—Michael Potts

Reference:
Huang Y, Cai X, Mai W, Li M, Hu Y. Association between prediabetes and risk of cardiovascular disease and all-cause mortality: systematic review and meta-analysis [published online November 23, 2016]. BMJ. doi:http://dx.doi.org/10.1136/bmj.i5953.