AMBULATORY BLOOD-PRESSURE IN DIABETIC SUBJECTS

Ambulatory blood pressure (ABP) was measured every 15 min for 24 h in 82 diabetic subjects aged 35 to 79 years and in 66 healthy controls ha ving the same age and office blood pressure. The autonomic control in diabetic subjects was evaluated by the total score of five cardiovascu lar function tests (a high score means an autonomic neuropathy). The d iurnal cycle of BP was assessed by the difference of BP between daytim e and nighttime (Delta BP = BP in the day - BP in the night). The vari ability of BP was evaluated by the standard deviations of the readings . Compared with control subjects, diabetic subjects had the same 24-h mean level of BP, a smaller Delta BP, and an increased variability dur ing the daytime; however, the differences were in the limit of statist ical significance. Clearcut results were obtained in diabetic subjects with autonomic neuropathy. In the latter, the score of autonomic neur opathy was (1) negatively correlated to Delta SBP (systolic) and Delta DBP (diastolic) (r = 0.44, P = .0004 and r = 0.46, P = .0004, respect ively) and (2) positively correlated to the variability of SBP and DBP during the daytime (r = 0.46, P .0004 and r = 0.29, P = .03, respecti vely). In diabetic subjects, mean level and variability of ABP were po sitively correlated to urinary microalbumin. The relationships were th e most significant when one relates microalbuminuria to the level of S BP in the night (r = 0.42, P < .0003) and to the variability of SBP in the day (r = 0.32, P = .008). Our data suggest that BP in diabetic su bjects with severe autonomic neuropathy is less prone to a decrease at night and is more sensitive to the subject's activities.