ON THE USE OF AMBULATORY BLOOD-PRESSURE RECORDINGS AND INSULIN SENSITIVITY MEASUREMENTS IN SUPPORT OF THE INSULIN-HYPERTENSION HYPOTHESIS

Objective: To determine the possible correlations between ambulatory b lood pressure and insulin sensitivity, compared with correlations betw een office blood pressure and insulin. Design: Observational study. Se tting: Policlinic at the Department of Geriatrics, Uppsala, Sweden. Pa tients: Caucasian patients (n = 149) of both sexes with untreated esse ntial hypertension. Main outcome measures: The hyperinsulinaemic eugly caemic clamp and office blood pressure in all subjects. In subgroups, also the oral glucose-tolerance test (n = 96) and 24-h ambulatory bloo d pressure (n = 84). Results: Significant correlations were seen betwe en the insulin sensitivity index and ambulatory blood pressure recordi ngs, whereas fasting plasma insulin levels were uncorrelated with offi ce blood pressure. The insulin sum and the 2-h insulin level of the or al glucose-tolerance test were more closely correlated with ambulatory blood pressure recordings than was the fasting insulin level. In mult iple regression analyses the night-time diastolic blood pressure showe d a significant correlation with the insulin sensitivity index even af ter controlling for the effects of sex, age and body mass index. Concl usion: The apparent association between blood pressure and insulin res istance not only is obscured by measurement error, but is also affecte d by the particular measures of insulin resistance and blood pressure used. The present study provides further evidence that a relationship exists between blood pressure and hyperinsulinaemia or insulin resista nce.