Sex differences in frailty and the impact of frailty on blood pressure control in older adults with hypertension: a multi-center observational study in Vietnam

Background Frailty is common in older adults with hypertension and can affect blood pressure (BP) control. Sex differences related to frailty and cardiovascular physiology may contribute to the effective treatment of hypertension. Aim to examine the prevalence of frailty in older adults with hypertension and its association with uncontrolled BP, with a particular focus on differences by sex. Methods This study was conducted at the outpatient clinics of two major hospitals in Vietnam from June 2023 to June 2024. Frailty was defined by a Clinical Frailty Scale of ≥4. Uncontrolled BP was defined as systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, averaged over recordings in the last 6 months. Multivariable logistic regression was applied to identify the association between frailty and uncontrolled BP. The odds ratios (ORs) for uncontrolled BP of each risk factor were estimated by sex, with interaction terms fitted between each risk factor and sex to obtain the women-to-men ratio of ORs (ROR). Results There were 1038 participants (326 women, 712 men). They had a mean age of 73.3 (SD7.4). The prevalence of frailty was 28.6% in all participants, higher in women (35.3%) than men (25.6%), p=0.001. The overall rate of uncontrolled BP was 26.7%. In women, the frail had a significantly higher rate of uncontrolled BP (33.9%) compared to the non-frail (20.9%), but no significant differences among men (26.4% in the frail vs. 27.5% in the non-frail). The adjusted ORs of frailty on uncontrolled BP were 1.70 (1.00–2.90) in women, 0.84 (0.57–1.25) in men; women-to-men ROR 2.02 (1.04–3.92). Conclusion In older adults with hypertension, frailty was more common in women and was associated with an increased risk of having uncontrolled BP in women only. These findings highlight the need for sex-specific approaches in managing hypertension in older populations.