Patients whose fasting plasma glucose (FPG) and 2-hour plasma glucose levels are both within the normoglycemia range are not necessarily off the hook. If their 2-hour glucose levels are higher than baseline, they’re at increased risk for insulin resistance and cardiovascular death, a new study shows….
Lead author Dr. Qing Qiao stated that, “A few studies have shown that when 2-hour plasma glucose does not return to FPG levels, patients are at significantly higher risk for Type 2 diabetes and a worse cardiovascular risk-factor profile compared to patients whose plasma glucose levels do return to baseline…. We have further shown that these people’s cardiovascular disease mortality was also high.” Their risk for other causes of death was not affected, according to research.
Dr. Qiao, from the University of Helsinki, Finland, and colleagues analyzed data from DECODE, an epidemiological study with 75-g oral glucose tolerance test results. They selected 12,566 men (53.6% of the participants) and 10,874 women (46.4%) in 19 European cohorts with normal plasma glucose levels. For inclusion in the study, the FPG cutoff was 110mg/dL.(6.1 mmol/L) and the 2-hour plasma glucose cutoff was 140mg/dL.(7.8 mmol/L.)
The median follow-up time was 9 years (range, 5 to 37). During that time, 1,437 men and 597 women died, including 827 men and 246 women who died of cardiovascular disease.
The researchers divided the participants into two groups, depending on whether their glucose levels returned to baseline (n = 10,759) or not (n = 12,681). The group with higher-than-baseline 2-hour glucose levels had higher mean age, body mass index, blood pressure and fasting insulin level.
With results adjusted for age, cohort, FPG, body-mass index, total cholesterol, smoking and hypertension, elevated 2-hour plasma glucose level was associated with hazard ratios for cardiovascular death of 1.22 in men and 1.40 in women.
Regardless of fasting insulin levels, subjects whose 2-hour glucose levels did not fall back to baseline had higher glucose concentrations in general compared to the other group, suggesting that they were already insulin resistant, the investigators said.
“Insulin resistance and the clustering of the insulin resistance with other metabolic disorders such as obesity and hypertension might be associated with the increased cardiovascular disease mortality” observed in this study, according to the authors.
Diabetes Care online April 27, 2010.