The aim of this study was to evaluate the relationship between nocturnal blood pressure (BP) (by ambulatory blood pressure monitoring, ABPM) and urinary albumin excretion (UAE) in hypertensive patients with type II diabetes mellitus. We studied 179 essential hypertensives (WHO I-II), all males, with non-insulin-dependent diabetes. Noninvasive ABPM was performed by a fully automatic, portable device (Spacelabs 90202), set to take readings at 15-min intervals during both daytime 7 AM to 1 PM and nighttime (1 PM to 7 AM). According to the day/night reduction in mean blood pressure (MBP), three groups were identified: group I, nocturnal MBP reduction >10%; group II, day/night MBP reduction of 5% to 10%; and group III, day/night MBP reduction <5%. The mean values of UAE as well as the prevalence of microalbuminuria (UAE >30 mg/24 h) were found to be significantly higher in group III as compared to the other two groups. Besides, in group III UAE displayed a significant negative relationship with the SBP and MBP (but not DBP) nocturnal drop and a positive relationship with the duration of hypertension and duration of diabetes. In group II, UAE was weakly correlated only with the duration of hypertension, whereas in group I no significant correlation was found between UAE and other parameters of the study. These results indicate that in hypertensive type II diabetic patients a blunted nocturnal BP fall is associated with higher UAE and increased prevalence of microalbuminuria. Whether the reduced day/night BP difference is the cause or consequence of target organ damage remains to be established.
