Reproducibility of nocturnal blood pressure fall in early phases of untreated essential hypertension: a prospective observational study

Abstract

A number of studies have shown that a smaller than normal nocturnal blood pressure (BP) decrease is associated with cardiovascular disease. However, no large prospective studies have examined the reliability of nocturnal dipping within individuals. The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension. In all, 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic (mean age 46712 years; 257 M, 157 F) prospectively underwent: (1) repeated clinic BP measurements; (2) routine examinations recommended by WHO/ISH guidelines; and (3) ambulatory BP monitoring (ABPM) twice within a 4-week period. Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10% compared to average daytime values. Overall, 311 patients (75.1%) showed no change in their diurnal variations in BP. Of the 278 patients who had a dipping pattern on the first ABPM, 219 (78.7%) confirmed this type of profile on the second ABPM, while 59 (21.3%) showed a nondipping pattern. Among 37 dipper patients with 420% of nocturnal systolic BP decrease (extreme dippers), only 16 (43.2%) had this marked fall in BP on the second ABPM. Of the 136 patients who had a nondipping pattern on the first ABPM, 92 (67.6%) confirmed their initial profile on the second ABPM, while 44 (32.4%) did not. Patients with reproducible nondipping profile were older (48712 years) than those with reproducible dipping profile (44712 years, Po0.05). These findings indicate that: (1) short-term reproducibility of nocturnal fall in BP in untreated middleaged hypertensives is rather limited: overall, one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks; (2) this was particularly true for extreme dipping and nondipping patterns; (3) abnormalities in nocturnal BP fall, assessed by a single ABPM, cannot be taken as independent predictors of increased cardiovascular risk.

Masked nocturnal hypertension—a novel marker of risk in type 2 diabetes

“…First, MNHT status was determined according to a single ambulatory BP measurement. The high degree of intra-individual variation of nocturnal BP patterns in patients with hypertension [27] means that it could be argued that repeated ambulatory BP measurements are needed in order to determine the true prevalence of MNHT. However, it was recently shown that short-term reproducibility of nocturnal BP patterns is higher in patients with type 2 diabetes (88.9%) than in patients without diabetes (70.5%) [28].…”

Pattern of 24-Hour Ambulatory Blood Pressure Monitoring in Type 2 Diabetic Patients with Cardiovascular Dysautonomy

“…Another problem when evaluating dipping or nondipping status is the limited reproducibility of nocturnal BP variability. This limitation is related to changes in day activities and sleep quality, besides the "regression to the mean" phenomenon that occurs when repeating ABPM in patients previously classified as extreme dippers or nondippers and risers (33,34). Otherwise, the reproducibility of dipping status was recently reported to be more reliable in diabetic than in nondiabetic hypertensive patients (35).…”

Isolated Nocturnal Hypertension

“…19 This long-term reproducibility was comparable with the short-term reproducibility of nondipping status between 2 ambulatory blood pressure recordings repeated within 4 weeks. 23 To the best of our knowledge, only 1 study compared the short-term reproducibility of nocturnal hypertension and nocturnal dipping status defined according to absolute blood pressure level and relative day-to-night blood pressure changes, respectively. 24 In an analysis in hypertensive patients who enrolled in a placebo-controlled clinical trial and had 2 repeated ambulatory blood pressure recordings 4 to 8 weeks apart, the reproducibility of nocturnal hypertension (≥125/80 mm Hg, κ statistic ≥0.46) was much higher than that of nocturnal nondipping (<5% or <10% of daytime blood pressure, κ statistic ≤0.38).…”