Adults with post-challenge hyperglycemia may be at increased risk for CVD

Older adults who have impaired glucose tolerance or a mild form of diabetes may be at an elevated risk for heart disease and may benefit from preventive therapies.

"Post-challenge hyperglycemia is very common and is considered to be a characteristic metabolic profile in older adults. Almost 25% of people aged 65 years and older will have some form of post-challenge hyperglycemia, whether IGT or diabetes," Jill P. Crandall, MD, associate professor of clinical medicine at Albert Einstein College of Medicine of Yeshiva University in New York City, told Endocrine Today.

“In most cases, this mild form of high blood glucose causes no symptoms and is often overlooked by both doctors and patients, but studies have shown that it may be associated with increased risk for heart disease,” said Crandall, also director of the Diabetes Clinical Trials Unit.

Presence established

The cross-sectional study included 58 adults; 30 with normal glucose tolerance and 28 with post-challenge hyperglycemia (fasting glucose ≤126 mg/dL and two-hour glucose ≥170 mg/dL).

Presence of post-challenge hyperglycemia was associated with fasting and postprandial metabolic alterations and accompanied by a pro-atherosclerotic and pro-thrombotic vascular profile when adults were challenged with an oral glucose load, according to the researchers.

These older adults with post-challenge hyperglycemia had higher levels of fasting glucose (102 mg/dL vs. 93 mg/dL; P<.001) and HbA1c (5.7% vs. 5.4%; P=.01) than those with normal glucose tolerance. This group was also more insulin resistant, as reflected by homeostasis model assessment of insulin resistance (7 vs. 4.1; P=.03), and had higher levels of fasting high-sensitivity C-reactive protein (2.6 mg/dL vs. 1.3 mg/dL; P=.05).

After the standard high carbohydrate meal, both peak (187 mg/dL vs. 142 mg/dL; P<.0001) and six-hour (910 mg/dL per hour vs. 747 mg/dL per hour; P<.0001) postprandial area under the curve glucose were greater in the group with post-challenge hyperglycemia. Levels of fasting and postprandial plasminogen activator inhibitor 1 were also higher among adults with post-challenge hyperglycemia. Levels of adiponectin were lower in this group (11.6 mcg/mL vs. 14 mcg/mL; P=.03), also consistent with increased vascular risk.

Endothelial function, as determined by reactive hyperemia peripheral arterial tonometry, declined in the post-challenge hyperglycemia group.

“All of these changes are negative in terms of heart disease risk. Adults who have this type of post-challenge hyperglycemia definitely have evidence of an increased cardiovascular risk profile,” Crandall said.

Hyperglycemia screening

Routine screening of the elderly using the standard oral glucose tolerance test could be used to identify these high-risk individuals. Despite the results of this study, it has not been established whether treatment aimed at reducing mild hyperglycemia will lower their risk for heart disease.

Crandall suggested that adults with post-challenge hyperglycemia should receive more careful attention to treatment of the usual CV risk factors.

"Consequently, other interventions designed to reduce CVD risk, including the use of statins and aspirin, should be strongly considered for older adults with impaired fasting glucose and post-challenge hyperglycemia," the researchers wrote. - by Katie Kalvaitis

Crandall JP. J Clin Endocrinol Metab. 2009;doi:10.1210/jc.2008-1829.