Combined Duration and Degree of Hypertension a Better Correlation with Cardiovascular Risk
In the past researchers have found that a combined consideration of both duration and degree of being overweight is a better reflection of long-term health risks than a measure of weight made of any single point in time. This is reflective of underlying processes that cause lasting damage. Analogously, researchers here show that measuring the duration and degree of high blood pressure, hypertension, produces better correlations with cardiovascular disease risk than single measures at a point in time. Raised blood pressure causes structural damage to delicate tissues, leads to cardiac hypertrophy, accelerates the development of atherosclerosis, and raises the risk of a weakened blood vessel or atheroma rupturing to produce a heart attack or stroke. Some of this is a matter of lasting harm that will persist after blood pressure is reduced, at least in the context of today's medical technologies and capabilities.
Cumulative blood pressure (BP), a measure incorporating the level and duration of BP exposure, is associated with the risk of cardiovascular disease (CVD). However, the level at which cumulative BP could significantly increase the risk remains unclear. This study aimed to investigate the association of 15-year cumulative BP levels with the long-term risk of CVD, and to examine whether the association is independent of BP levels at one examination.
Data from a 26-year follow-up of the Chinese Multi-provincial Cohort Study-Beijing Project were analyzed. Cumulative BP levels between 1992 and 2007 were calculated among 2429 participants free of CVD in 2007. Cardiovascular events (including coronary heart disease and stroke) occurring from 2007 to 2018 were registered. Adjusted hazard ratios (HRs) for CVD incidence associated with quartiles of cumulative systolic blood pressure (SBP) and diastolic blood pressure (DBP) were calculated.
Of the 2429 participants, 42.9% (1042) were men, and the mean age in 2007 was 62.1 ± 7.9 years. Totally, 207 CVD events occurred during the follow-up from 2007 to 2018. Participants with higher levels of cumulative SBP or DBP exhibited a higher incidence rate of CVD. Compared with the lowest quartile of cumulative SBP, the HR for CVD was 1.03, 1.69, and 2.20 for the second to the fourth quartile of cumulative SBP, and 1.46, 1.99, and 2.08 for the second to the fourth quartile of cumulative DBP, respectively.
In conclusion, our study demonstrated that elevated cumulative SBP or DBP was independently associated with increased risk of CVD in the Chinese population. Among participants with 15-year cumulative BP levels higher than the median, that is, 1970.8/1239.9 mmHg-year for cumulative SBP/DBP, which was equivalent to maintaining SBP/DBP level higher than 131/83 mmHg in 15 years, the CVD risk would increase significantly irrespective of whether or not the BP measurements at one examination was high. Our findings emphasize the importance of cumulative BP level in identifying individuals with high risk of CVD in the future.