Pulse Pressure Independent of Mean Arterial Pressure Is Associated with Cardiovascular and All-Cause Mortality in Normotensive Elders: Findings from National Health and Nutrition Examination Survey III 1999–2014

Abstract

Background: Pulse pressure (PP), a marker of arterial stiffening, is closely related to adverse outcomes in hypertensive patients. Correspondingly, less attention has been paid to the value of PP in the population with normal blood pressure. Methods: The study included normotensive elders aged over 60 years from the 1999–2014 National Health and Nutrition Examination Survey (NHANES). All included participants were followed up until the date of death or 31 December 2015. Restricted cubic spline analyses were used to explore the associations of PP with cardiovascular mortality and all-cause mortality. The population was categorized into two groups according to the optimal cut-off of PP for all-cause mortality by X-tile software. Propensity matching score analysis was further performed to reduce confounding bias. The Kaplan–Meier curves and Cox proportional hazard models were applied to estimate the associations of widening PP cardiovascular mortality and all-cause mortality. Subgroup analyses were also conducted. Results: A total of 6309 participants were included (52.9% men and median age 69 (63, 75) years). The median follow-up duration was 74 (42, 114) months. The restricted cubic spline analyses revealed that continuous PP was linearly related to cardiovascular mortality (p for linearity < 0.001; p for nonlinearity = 0.284) and nonlinearly related to all-cause mortality (p for nonlinearity = 0.001). After propensity score matching, 1855 subjects with widening PP and 1855 matched counterparts were included (50.2% men and average age 72 (66, 78) years, 50.9% men and average age 72 (66, 78) years, respectively), of which 966 (26.0%) died during a median follow-up duration of 71 (39, 105) months. In the Cox proportional hazards model, widening PP was associated with increased cardiovascular mortality Hazard Ratio (HR) 1.47; 95% Confidence Interval (CI) 1.07–2.00, p < 0.05] and all-cause mortality (HR 1.15; 95% CI 1.01–1.31, p < 0.05). After adjusting for other traditional risk factors, the association of widening PP with cardiovascular mortality (HR 1.44; 95%CI 1.05–1.98, p < 0.05) remained, and the association of widening PP with all-cause mortality was not statistically significant (p > 0.05). Conclusion: In the normotensive elder population, a low-risk population without traditional coronary risk factors, PP is an independent risk factor for cardiovascular mortality.