Diurnal correlation of ambulatory blood pressure and interstitial glucose in patients with normal glucose tolerance

OBJECTIVE: Among the physiological variables whose diurnal profile is governed by circadian rhythmicity, plasma glucose concentrations, and arterial blood pressure constitute key elements of the physiological regulation of energy homeostasis. Evidence on their diurnal association derived from frequent measurements of both variables is, however, lacking in humans. METHODS: We investigated the relationship between blood pressure levels recorded by an ambulatory device and interstitial glucose concentrations on an outpatient basis, in patients with normal glucose tolerance (N=20), either normotensive (group A; N=10), or newly diagnosed with essential hypertension (group B; N=10). RESULTS: In the population throughout the 24-h monitoring period, there was a significant positive correlation between interstitial glucose concentrations and systolic, diastolic, and mean 24-h blood pressure levels, which was retained in patients with hypertension compared with normotensive patients. In patients with newly diagnosed hypertension, interstitial glucose concentrations exhibit significant correlation to systolic blood pressure levels during the 24-h period, but no association with diastolic and mean blood pressure during the night, whereas the reverse is the case in patients with normal glucose tolerance and normal blood pressure. CONCLUSION: Diurnal variations of continuously monitored interstitial glucose concentrations significantly associate with blood pressure levels in both normotensive and hypertensive humans, indicating a common pathway of circadian autoregulation, probably stemming from both central mechanisms and peripheral inputs. Such a pathway might underlie similar pathophysiological aberration in disease states such as the metabolic syndrome.