Circadian Pattern of Ambulatory Blood Pressure in Hypertensive Patients With and Without Type 2 Diabetes

Abstract

There is strong association between diabetes and increased risk of end-organ damage, stroke, and cardiovascular disease (CVD) morbidity and mortality. Non-dipping (<10% decline in the asleep relative to awake blood pressure [BP] mean), as determined by ambulatory BP monitoring (ABPM), is frequent in diabetes and consistently associated with increased CVD risk. The reported prevalence of non-dipping in diabetes is highly variable, probably due to differences in the study groups (normotensive subjects, untreated hypertensives, treated hypertensives), relatively small sample sizes, reliance only on a single, low-reproducibility, 24-h ABPM evaluation per participant, and definition of daytime and nighttime periods by arbitrary selected fixed clock-hour spans. Accordingly, we evaluated the influence of diabetes on the circadian BP pattern by 48-h ABPM (rather than for 24 h to increase reproducibility of results) during which participants maintained a diary listing times of going to bed at night and awakening in the morning. This cross-sectional study involved 12 765 hypertensive patients (6797 men/5968 women), 58.1 ± 14.1 (mean ± SD) yrs of age, enrolled in the Hygia Project, designed to evaluate prospectively CVD risk by ABPM in primary care centers of northwest Spain. Among the participants, 2954 (1799 men/1155 women) had type 2 diabetes. At the time of study, 525/3314 patients with/without diabetes were untreated for hypertension, and the remaining 2429/6497 patients with/without diabetes were treated. Hypertension was defined as awake systolic (SBP)/diastolic (DBP) BP mean ≥135/85 mm Hg, or asleep SBP/DBP mean ≥120/70 mm Hg, or BP-lowering treatment. Hypertensive patients with than without diabetes were more likely to be men and of older age, have diagnoses of microalbuminuria, proteinuria, chronic kidney disease, obstructive sleep apnea, metabolic syndrome, and/or obesity, plus higher glucose, creatinine, uric acid, and triglycerides, but lower cholesterol and estimated glomerular filtration rate. In patients with diabetes, ambulatory SBP was significantly elevated (p < .001), mainly during the hours of nighttime sleep and initial hours after morning awakening, independent of presence/absence of BP-lowering treatment. Ambulatory DBP, however, was significantly higher (p < .001) in patients without diabetes, mainly during the daytime. Differing trends for SBP and DBP between groups resulted in large differences in ambulatory pulse pressure (PP), it being significantly greater (p < .001) throughout the entire 24 h in patients with diabetes, even after correcting for age. Prevalence of non-dipping was significantly higher in patients with than without diabetes (62.1% vs. 45.9%; p < .001). Largest difference between groups was in the prevalence of the riser BP pattern, i.e., asleep SBP mean greater than awake SBP mean (19.9% vs. 8.1% in patients with and without diabetes, respectively; p < .001). Elevated asleep SBP mean was the major basis for the diagnosis of hypertension and/or inadequate BP control among patients...

Sleep-time BP: prognostic marker of type 2 diabetes and therapeutic target for prevention

“…Night-time hypertension and non-dipper BP patterning are highly prevalent in diabetes and these features have been consistently associated with the increased CVD risk of patients with diabetes [23][24][25][26][27]. For instance, a recent cross-sectional study involving 12,765 patients with hypertension according to current ABPM criteria-awake systolic (SBP)/diastolic (DBP) BP mean ≥135/85 mmHg or asleep SBP/DBP mean ≥120/70 mmHg [28,29]-that included 2,954 participants with type 2 diabetes, found the prevalence of non-dipping was significantly higher in patients with than without diabetes (62.1% vs 45.9%; p <0.001) [27].…”

“…For instance, a recent cross-sectional study involving 12,765 patients with hypertension according to current ABPM criteria-awake systolic (SBP)/diastolic (DBP) BP mean ≥135/85 mmHg or asleep SBP/DBP mean ≥120/70 mmHg [28,29]-that included 2,954 participants with type 2 diabetes, found the prevalence of non-dipping was significantly higher in patients with than without diabetes (62.1% vs 45.9%; p <0.001) [27]. Furthermore, elevated sleep-time SBP mean was the major basis for the diagnosis of hypertension and/or inadequate BP control among patients with diabetes; thus, among the uncontrolled hypertensive patients with diabetes, 89.2% had sleep-time hypertension [27].…”

Non-Dipping Phenomenon; is it Reversible in Diabetic Hypertensive Cases?

“…control of morning BP rise and daytime and nighttime SBP/DBP means plus normalization of the atypical non-dipping 24 h SBP/DBP profile [6]. the reproducibility of non-dipping is higher in diabetic patients than in the general population (International ABPM Registry ARTEMIS).…”

Elevated asleep BP as predictor of type 2 diabetes and therapeutic target for prevention

“…We believe the additional assumed limitations described in the accompanying commentary [1] are invalid and do not in any way diminish the scientific merit of our findings. Nonetheless, as previously acknowledged [2,3], future prospective intervention trials that incorporate annual or more frequent around-the-clock ABPM assessments during long-term follow-up evaluation, as carried out in the completed MAPEC study and the currently ongoing multicentre Hygia Project (involving more than 18,000 participants) [17,18], are necessary. This is important, first, to confirm that the asleep SBP mean is a sensitive predictor of risk of diabetes and, second, to determine the merit of bedtime hypertension chronotherapy to avert diabetes through normalisation of asleep SBP mean, which may be mediated by improved effects on those circadian rhythms that regulate in common asleep BP and metabolic processes [19].…”