Sex is not a reliable indicator of the individual hemodynamic phenotype between women and men with high blood pressure, particularly older adults, a new Yale-led study concludes.
The study was published June 14 in PLOS ONE.
The importance of sex-specific differences among adults with hypertension is not well-understood. For the study, Dr. César Caraballo-Cordovez, a postdoctoral associate at the Yale-based Center for Outcomes Research and Evaluation (CORE), and colleagues used data on over 45,000 individuals throughout China. Elevated blood pressure was defined as systolic blood pressure over 130 mmHg and a diastolic blood pressure (DBP) of ≥80 mmHg. The authors investigated if there were sex-specific hemodynamic profiles that ultimately might be tested in sex-specific recommendations for antihypertensive therapy.
“High blood pressure or hypertension contributes to the global burden of cardiovascular disease, stroke, and renal diseases,” said Caraballo-Cordovez. “We evaluated if there were sex differences in hypertension phenotypes that could be used to develop therapies tailored for each patient’s characteristics.”
The study, believed to be the most comprehensive comparison of hemodynamic variables and phenotypes between women and men, is a collaboration between researchers at CORE, the SJTU-Yale Joint Center for Biostatistics in Shanghai, China, and iKang Health Group.
The authors examined common cardiovascular variables — mainly cardiac index (CI) and systemic vascular resistance (SVRI). Both of these factors, individually or together, contribute to blood pressure and can be used to determine the hemodynamic profile. After adjusting for age and other factors, young women had lower SVRI and higher CI than men of their same age, results that were reversed among those older than 50 years (the average age of menopause in China). However, the distribution of CI and SVRI overlapped substantially between women and men. Notably, these variables were nearly identically distributed among women and men older than 50.
The research team concluded that sex-specific patterns existed but were not specific enough to use sex alone to characterize which hemodynamic pattern (the balance of blood ejected from the heart and the tone of the blood vessels) was responsible for the elevated blood pressure.
“Our study has important implications for the underlying mechanisms of hypertension in different groups, but also indicates to need to measure each person rather than to assume a profile based on their sex,” said senior author Dr. Harlan M. Krumholz, the Harold H. Hines Jr. Professor of Medicine at Yale and director of CORE. “Further research is needed to determine whether tailoring treatment to a particular underlying cause of the high blood pressure could prevent or delay the consequences of high blood pressure.”
Yale’s Shiwani Mahajan, Yuan Lu, Erica S. Spatz, Rachel P. Dreyer are co-authors of the paper. Other authors are Jianlei Gu, Hongyu Zhao, Hui Lu, Zheng J. Ma from the SJTU-Yale Joint Center for Biostatistics; Mao Zhen Zhang, Shanghai Jiao Tong University; Ning Ling Sun, Peking University People’s Hospital; Yihong Ren, The First Medical Center of Chinese PLA General Hospital; Xin Zheng, iKang Healthcare Group.