Nocturnal Blood Pressure Fall on Ambulatory Monitoring in a Large International Database

Abstract

A wide range of definitions is used to distinguish subjects in whom blood pressure (BP) falls at night (dippers) from their counterparts (nondippers). In an attempt to standardize the definition of nondipping, we determined the nocturnal BP fall and night-day BP ratio by 24-hour ambulatory monitoring in 4765 normotensive and 2555 hypertensive subjects from 10 to 99 years old. In all subjects combined, the systolic/diastolic nocturnal fall and corresponding ratio averaged (+/- SD) -16.7 +/- 11.0/ -13.6 +/- 8.1 mm Hg and 87.2 +/- 8.0%/83.1 +/- 9.6%, respectively. In normotensive subjects, the 95th percentiles were -0.3/-1.1 mm Hg for the nocturnal fall and 99.7%/98.3% for the night-day ratio. Both the fall and ratio showed a curvilinear correlation with age. The smallest fall and largest ratio were observed in older (> or = 70 years) subjects. A higher BP on conventional sphygmomanometry was associated with a larger systolic (partial r = .11) and diastolic (r = .12) nocturnal BP fall. The diastolic (r = .08) but not the systolic night-day ratio increased with higher conventional BP. The nocturnal BP fall was larger and the corresponding night-day ratio smaller in oscillometric (n = 5884) than in auscultatory (n = 1436) recordings, in males (n = 3730) than in females (n = 3590), and in Europe (n = 4556) than in the other continents (n = 2764). The distributions of the nocturnal BP fall and night-day ratio showed considerable overlap among normotensive and hypertensive subjects, but the overlap tended to be larger for the ratio than for the fall. Of all subjects, 3.2% had systolic and diastolic ratios of 100% or more. With adjustments applied for confounders, the probability of being a nondipper increased 2.8 times (95% confidence interval, 2.0-4.0) from 30 to 60 years and 5.7 times (4.4-7.4) from 60 to 80 years. The odds ratios were 1.0 (0.8-1.4) for males versus females. 1.6 (1.2-2.1) for subjects with definite hypertension versus normotensive subjects, 2.4 (1.2-4.7) for Asians (n = 2213, 96% Japanese) versus inhabitants of the other continents, and 2.4 (1.5-3.8) for subjects examined with auscultatory versus oscillometric devices. In conclusion, the mathematical definition of nondipping, ie, having a night-day ratio of 100% or more for systolic and diastolic BPs, closely approximated the 95th percentiles of the night-day ratio in normotensive subjects. The ratio depends less on BP level than the nocturnal BP fall and is therefore to be preferred in the definition of dipping status. Notwithstanding the present findings, the reproducibility of nondipping and its prognostic significance need further clarification.

Usefulness of ambulatory blood pressure monitoring in predicting the presence of autonomic neuropathy in type I diabetic patients

“…The cutoff values of day-night difference in BP that we found to be more appropriate for identifying patients with autonomic neuropathy, approximate to the 95th percentile of the distribution of day-night variation in BP in a large international database in normotensive subjects. 20 Moreover, Hansen et al 32 found that in 137 normoalbuminuric normotensive adult type I diabetic patients, the 95th percentile level of the daynight difference in SBP and DBP were 3 and 6%, respectively, which as values are rather similar to those identified by us as appropriate diagnostic cutoff points for autonomic neuropathy (i.e. 0 and 5%).…”

“…In a multiple logistic regression after adjustment for the clinical correlates known to affect nocturnal BP fall in the general population, 20 that is sex, age, and body mass index, the odds ratio for having autonomic neuropathy was seven times higher in Nondipping as diagnostic tool for autonomic neuropathy V Spallone et al systolic nondippers as opposed to systolic dippers (odds ratio 6.97, 95% CI 1.4-34.9, P ¼ 0.018).…”

“…19,20 According to the distribution of the day-night variation in BP in the general population, it has been proposed to lower the cutoff for the definition of nondipping to 0%, that identifies a complete loss of the day-night change in BP and corresponds to the 95th percentile of the distribution in a large international database in normotensive subjects. 20 Thus, we investigated whether nondipping could be assumed as a diagnostic index for autonomic neuropathy, and assessed its accuracy in discriminating between type I diabetic patients with and without autonomic neuropathy. Moreover, we evaluated the best cutoff of the percentage nocturnal BP fall in identifying patients with autonomic neuropathy.…”

Sympathoadrenergic and metabolic factors are involved in ambulatory blood pressure rise in childhood obesity

“…The non-dipping status was defined as a night-time/daytime SBP or DBP ratio X100%. 22 Biochemical measurements Plasma glucose, cholesterol, triglycerides and uric acid concentrations were measured on an automated analyser (Roche Diagnostics, Mannheim, Germany). Serum insulin was measured in duplicate by a chemiluminescent assay (DPC, Los Angeles, CA, USA; sensitivity 14.3 pmol l À1 and intra-and interassay coefficients of variation (CVs) 3.7 and 6.7%, respectively).…”

Diurnal blood pressure patterns in normotensive and hypertensive children and adolescents

“…12 multiplied by 100 to express the night-time BP as a percentage of the mean daytime SBP, DBP and Subjects with a history of elevated BP were categorized as borderline hypertensive if the average sys-MAP. 16 Cusums and cusum-derived statistics were calculated as described elsewhere. 17 Briefly, this tolic or diastolic BP on at least three separate occasions within 3 months of the monitoring period method involves subtracting the time-weighted mean 24-h BP from each successive BP measurewas between the 90th and 95th percentiles for age and gender or as having hypertension if above the ment, adding these deviations adjusted for the length of the preceding time interval and plotting 95th percentile.…”