Prevalence and influencing factors of masked uncontrolled hypertension among Chinese female patients with clinically controlled hypertension

Background and aims: Hypertension is a leading modifiable risk factor for cardiovascular disease (CVD) and mortality. The high risk of CVD and mortality observed in patients with controlled office blood pressure may be associated with masked uncontrolled hypertension (MUCH). Previous studies have shown that females with hypertension tend to have lower rates of blood pressure control than males. However, data on blood pressure control during daily life among female patients with treated hypertension are limited, and the prevalence of MUCH among those with clinically controlled hypertension remains unclear. Therefore, we aimed to investigate the prevalence, distribution, and influencing factors of MUCH among female patients with clinically controlled hypertension using a large, nationally representative survey. Methods: We analyzed data from the Chinese Cardiovascular Association Database-Hypertension Center collected between January 1, 2019 and December 31, 2023. Office blood pressure control was defined as <140/90 mmHg in patients with treated hypertension, in accordance with existing guidelines. In this population, MUCH was diagnosed as an average 24-h blood pressure ≥130/80 mmHg. Female patients with clinically controlled hypertension who completed 24-h ambulatory blood pressure monitoring (ABPM) were included in the analysis. The prevalence of MUCH was assessed in the overall population and across different groups. We also conducted a multivariable stepwise logistic regression analysis to identify influencing factors of MUCH. Results: A total of 10 527 female patients with clinically controlled hypertension were included, with an average age of 63.69 years, 5462 (51.89%) of whom were diagnosed with MUCH. The prevalence of MUCH among patients with borderline blood pressure control was 1.62-fold higher than that among those with optimal blood pressure control. Elevated office blood pressure, obesity, mixed dyslipidemia, smoking, and non-Han ethnicity were positively associated with MUCH, whereas higher educational level, hospitalization, menopause status, combination therapy of antihypertensive drugs, and longer duration of hypertension were negatively associated with MUCH. Suboptimal nighttime blood pressure control was the dominant contributor to the high prevalence of MUCH; the proportion of patients with nocturnal MUCH was approximately 12-fold higher than that of patients with exclusively daytime MUCH. Conclusions: The prevalence of MUCH remains high among female patients with clinically controlled hypertension, with suboptimal nighttime blood pressure control identified as the dominant contributing factor. Patients with obesity, smoking habits, and low education level represent high-risk populations and warrant targeted attention. Our findings suggest that office blood pressure measurements alone may be insufficient to achieve optimal blood pressure control among female patients. Consideration of 24-h ABPM may help improve the identification of MUCH and inform more individualized blood pressure management, particularly in high-risk populations.