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Altered circadian blood pressure profile and prognosis
Verdecchia1, Schillaci, Borgioni
1Ospedale Generale Regionale Raffaello Silvestrini, Area Omogenea di Cardiologia e Medicina, Perugia, Italy.
Insights
A blunted reduction in blood pressure from day to night, known as nondipping, significantly increases cardiovascular risk in both men and women. This finding holds true regardless of other risk factors or average blood pressure levels.
Area of Science:
- Cardiology
- Hypertension Research
- Chronobiology
Background:
- Previous studies indicated higher cardiovascular events in hypertensive nondippers compared to dippers, particularly in women.
- These differences persisted after multivariate analysis, adjusting for confounders like average 24-hour ambulatory blood pressure.
- Nondipping status was associated with increased cardiovascular endpoints irrespective of the definitions used for day/night or dipping thresholds.
Purpose of the Study:
- To investigate the prognostic value of a blunted diurnal blood pressure rhythm in a larger sample with extended follow-up.
- To assess this prognostic value across both sexes.
Main Methods:
- Utilized the night:day ratio of ambulatory blood pressure, a continuous variable.
- Defined nondipping based on the upper tertiles of the night:day systolic blood pressure ratio: > 0.899 for men and > 0.909 for women.
- Performed multivariate analysis to adjust for risk markers, including average 24-hour ambulatory blood pressure.
Main Results:
- A high night:day systolic blood pressure ratio identified individuals with elevated cardiovascular risk, independent of other risk factors.
- The prognostic value of the systolic night:day ratio remained significant after adjusting for multiple risk markers.
- The night:day diastolic blood pressure ratio did not emerge as a statistically significant independent predictor of cardiovascular risk.
Conclusions:
- A blunted diurnal blood pressure reduction (nondipping) predicts increased cardiovascular morbidity, even with well-controlled risk factors and average blood pressure.
- Specific thresholds for the night:day systolic blood pressure ratio can define nondippers with increased cardiovascular risk for both men and women.
- Ambulatory blood pressure monitoring and analysis of diurnal patterns offer valuable prognostic information for cardiovascular risk stratification.
Abstract:
BACKGROUND: In a previous analysis of the Progetto Ipertensione Umbria Monitoraggio Ambulatoriale we found a higher rate of cardiovascular morbid events among hypertensive nondippers than we did among dippers (5.86 versus 1.18 events per 100 person-years, P = 0.0002) for women, whereas the difference between the two groups was smaller and not statistically significant for men (4.15 versus 2.48 events per 100 person-years). These differences held in a multivariate analysis after adjustment for several confounders including average 24 h ambulatory blood pressure. In another analysis, the rate of occurrence of cardiovascular end-points was higher among nondippers than it was among dippers regardless of the definition of day and night (0600-2200 h and 2200-0600 h, awake and asleep, and 1000-2000 h and 2400-0600 h) and of the dividing line between dippers and nondippers (10 versus 0% day-night difference in blood pressure). OBJECTIVE: To test in a subsequent analysis based on a larger sample and a longer follow-up period, for both sexes, the prognostic value of a blunted diurnal rhythm of blood pressure. METHOD: We used the night: day ratio of ambulatory blood pressure, a continuous and normally distributed variable. RESULTS: A night: day systolic blood pressure ratio > 0.899 for men and > 0.909 for women (upper tertiles of distributions) identified a subset of subjects with greater than normal cardiovascular risk for any level of concomitant risk factors, wherease the hight:day diastolic blood pressure ratio was not statistically significant as an independent predictor. The excess risk for subjects in the upper tertile of the night: day systolic blood pressure ratio held after adjustment for several risk markers, including average 24 h ambulatory blood pressure. CONCLUSION: These data suggest that a blunted reduction in blood pressure from day to night predicts an increased cardiovascular morbidity at any level of concomitant risk factors including average 24 h ambulatory blood pressure. Nondippers can be defined in terms of a night: day ambulatory systolic blood pressure ratio > 0.899 for men and > 0.909 for women, regardless of the diastolic blood pressure profile.