Two hour glucose post loading: a biomarker of cardiovascular risk in isolated clinic hypertension

BACKGROUND: Isolated clinic hypertension (ICHT) may be an indicator of both future hypertension and diabetes. This study examines the 2-h plasma glucose level post load (2hPG), and measures of arterial stiffness, autonomic function and circulating biomarkers in ICHT, normotension and hypertension. METHODS: Participants aged 39-75 years, who were untreated for hypertension, nonsmokers and not known diabetic (n=105) were categorized as normotension, ICHT and hypertension, based on clinic and mean daytime ambulatory blood pressures. Participants had measurements of autonomic function, aorto-femoral pulse wave velocity (PWVc), as well as blood sampling for lipids and potential circulating biomarkers [high sensitivity C-reactive protein (hsCRP), plasminogen activator inhibitor 1 (PAI-1), asymmetric dimethylarginine (ADMA), and von Willebrand factor (vWF)], followed by a glucose tolerance test. RESULTS: A total of 8.3% normotension, 37.9% ICHT and 15% hypertension patients had impaired glucose tolerance. Mean 2hPG adjusted for age and waist circumference was 5.7 mmol/l [interquartile range (IQR) 5.2-6.4] for normotension, 7.4 mmol/l (IQR 6.5-8.3) for ICHT (P=0.002 vs. normotension) and 6.2 mmol/l (IQR 5.6-6.9) for hypertension group. Other measures of insulin resistance were similar in the three groups. Mental stress testing induced a greater blood pressure response in the ICHT group (P=0.01 vs. normotension); other autonomic function measures were similar in the three groups. Mean PWVc, adjusted for age and blood pressure, was similar in ICHT and normotension but increased in the hypertension group. Circulating biomarker levels were not different in the three groups. CONCLUSION: Assessment of total cardiovascular risk in patients with ICHT should include measurement of postprandial glucose.