Background
Population aging and increasing life expectancy have led to a rise in the incidence of chronic diseases and functional impairments, posing significant challenges to society and the healthcare system. Among the major health problems faced by older adults, hypertension shows a strong association with adverse health outcomes, including mortality [
1]. Moreover, the hypertension prevalence rate increases with age, demonstrating an upward trend worldwide [
2,
3]. In the context of aging, the risk of hypertension co-occurring with frailty advances with age, leading to a growing prevalence of this concurrent condition in older adults [
4]. Frailty is a geriatric syndrome involving a decline in multiple physiological reserves of the body, along with decreased resistance to stressors, heightened vulnerability, and diminished ability to maintain homeostasis. Frailty is also linked to an increased risk of disability, hospitalization, and death in older adults. The prevalence rate of frailty in older adults is 2.3%–20.2%, indicating an escalating trend with age [
5,
6].
The growing recognition of frailty as a health condition has resulted in a gradual increase in research investigating the relationship between frailty and hypertension. Frailty and hypertension in older adults have been suggested to have a reciprocal interaction. For example, chronic diseases such as hypertension are considered significant risk factors for frailty [
7], with hypertension-related cardiovascular complications being reported as contributing factors to frailty occurrence [
8]. Conversely, frailty is a suggested risk factor for cardiovascular diseases, including hypertension [
9]. The effects of coexisting frailty and hypertension have also been demonstrated in terms of adverse outcomes, with a few studies indicating that patients with hypertension accompanied by frailty experience a significant increase in the risk of death [
10,
11]. Therefore, strengthening the understanding of frailty in older adults with hypertension may be a crucial aspect of hypertension management. Correspondingly, researchers in developed countries have emphasized monitoring, assessing, and preventing frailty in patients with hypertension [
12‐
15]. However, only a few studies have been conducted on the interaction between hypertension and frailty, as well as its impact on long-term mortality. Although the community health services in China, which has an expanding population of older adults with hypertension living in the community, have prioritized the health management of the older population with hypertension, frailty is still not routinely screened for in this population [
16]. Therefore, this study aimed to analyze the prevalence of frailty and hypertension among older adults in an urban community in Beijing, as well as explore their interaction and its impact on 11-year mortality. We hope that our study will provide a solid basis for enhancing the management of frailty in older adults with hypertension, thereby reducing frailty-associated adverse health outcomes.
Discussion
Hypertension and frailty are two critical health issues that often occur concurrently, exhibiting increasing prevalence in the older population [
9]. Our study revealed that 49.5% of older adults in a Beijing community experienced hypertension in 2009.Furthermore, women were found to have a higher hypertension prevalence rate than men (54.7% vs. 41.7%), consistent with the findings of the China hypertension survey. The Chinese National Nutrition and Health Survey in 2002 also reported a hypertension prevalence of 49.1% among older adults aged ≥ 60 years [
22]. In support of these findings, a previous cross-sectional study conducted from 2012 to 2015 using multistage and stratified random sampling showed a hypertension prevalence of 53.2%.Moreover, the prevalence increased significantly with age and was observed in 51.1% and 55.3% of men and women, respectively [
23]. Additionally, we estimated that 12.6% of older adults in the Beijing community exhibited frailty. We further found that frailty showed increased prevalence with age and had a higher prevalence rate in women than in men, in line with the results of previous studies [
24,
25]. The comparison of the baseline results in this study revealed that older age, female gender, lower education levels, and widowed status were associated with a higher proportion of hypertension with frailty. Furthermore, a greater number of older adults with hypertension and frailty had three or more chronic diseases, multiple types of medication, a significant decline in the ADL and cognitive function, and an increase in depression scores, all of which were congruent with previous study findings [
10,
11,
15]. Therefore, the management of older adults with hypertension and frailty can be enhanced by implementing targeted interventions to delay disease progression, reduce the risk of complications, and minimize adverse outcomes. According to the current study results, older adults with hypertension had a higher prevalence of frailty than those without hypertension (15.0% vs. 10.3%). Moreover, older adults with hypertension exhibited higher baseline FI values than those without hypertension, regardless of their age. A prior meta-analysis indicated that 14.0% (95%
CI: 0.12–0.17) of patients with hypertension experienced frailty [
14]. Similarly, another investigation by Ma et al. [
11]showed that the prevalence rate of frailty among older adults with hypertension in China was 19.6%. Additionally, older adults with hypertension and frailty have been found to perform worse in physical, psychological, and social activities than those without frailty. Older adults with hypertension also have a low quality of life, experience several complications, use numerous medications, exhibit physical and cognitive deterioration, and have an elevated risk of falling, all of which contribute to frailty. Therefore, older adults with hypertension are associated with a greater risk of developing frailty [
26]. This relationship between hypertension and frailty may be explained by the common pathogenic mechanisms of cardiovascular disease and frailty in older adults with hypertension. For example, the activation of the chronic inflammatory process may serve as the prior pathogenic cause of the coexistence of hypertension with related cardiovascular diseases and frailty. Chronic inflammation is associated with the body’s homeostatic response after exposure to pathogens and involves pathophysiological changes in the nervous, musculoskeletal, endocrine, immune, and hematological systems. Therefore, hypertension and frailty in older individuals can often coexist with multiple diseases and promote each other [
27,
28]. Additionally, a previous cross-sectional study found that older adults with pre-frailty and frailty had a higher incidence of atherosclerosis, potentially explaining the relationship between frailty and cardiovascular diseases, such as hypertension [
29].
Our study also showed that the death rate of older adults with hypertension was higher than those without hypertension at any degree of frailty. Furthermore, the largest difference in the death rate between these patients was observed within the FI values ranging from 0.3 to 0.5, with this difference gradually decreasing with increasing frailty. Moreover, we performed a Cox regression analysis after adjusting for confounding factors, such as age, gender, education level, and marital status. The results showed that older adults with hypertension and frailty had the highest risk of death. Further analysis according to age revealed that older adults with both hypertension and frailty had an increased death risk in all three age groups, demonstrating that mortality risk is greatly influenced in older adults with hypertension accompanied by frailty than in those with only frailty or hypertension. Our study results suggested that the occurrence and development of hypertension and frailty in older adults are often mutually reinforcing and overlap. Previous research showed that the coexistence and interaction between hypertension and frailty was associated with a significantly increased death rate compared with the presence of hypertension alone [
30]. In a large longitudinal aging study in China, Ma et al. [
11]. adopted the FI to assess frailty in 1111 patients with hypertension who were ≥ 60 years old and found that compared to patients with hypertension but no frailty, patients with both hypertension and frailty had a higher 8-year death rate. Those study findings, combined with the results of our study, imply that older adults with hypertension and frailty are at higher risk of adverse outcomes than those with hypertension but no frailty. Further, these results suggest that healthcare professionals managing adults with hypertension should pay close attention to the screening and assessment of their frailty status, particularly those with mild or moderate frailty (FI value: 0.3–0.5). In terms of managing hypertensive older adults with frailty, determining the degree of frailty becomes crucial in balancing the benefits and risks of antihypertensive treatment in this specific older population. An earlier meta-analysis found that high systolic and diastolic blood pressure levels could reduce the overall death rate of older patients with frailty, with pulse pressure showing no association with death risk [
31]. In support of these observations, Odden et al. [
32]. also found that hypertension in older adults with frailty was linked to a lower death rate. However, the European Guidelines have highlighted the risk of overtreatment in older adults with frailty [
33], which can potentially increase the incidence of adverse events. Thus, assessing the frailty of hypertensive patients is imperative. The hypertension guidelines published by the International Society of Hypertension in 2020 suggest a target blood pressure of ≤ 140/90 mmHg for individuals who are ≥ 65 years old (if tolerated).Furthermore, the guidelines recommend that the treatment for meeting individualized blood pressure targets should be determined based on the frailty status, independent living capability, and tolerable conditions of the individuals [
34]. Moreover, the 2019 Chinese Guidelines for the Management of Hypertension in the Elderly [
35] suggest that antihypertensive drug treatment in the oldest-old individuals with frailty should be considered for blood pressure levels ≥ 160/90 mmHg. Furthermore, the target systolic blood pressure should be < 150 mmHg, with further reduction to < 140/90 mmHg if treatment is well tolerated. However, the systolic blood pressure can be as high as 130 mmHg [
36]. Additionally, the antihypertensive drugs used in older adults with frailty should be stable, effective, safe, and simple, as well as have only limited adverse effects and good compliance. The drugs should be initially administered in small doses, followed by a gradual increase or the use of small dose combinations.
This study has several limitations that should be considered. First, the data were obtained based on a questionnaire, thereby leading to potential information biases, including memory bias and questionnaire misinterpretation. Second, due to the prospective nature of this study, the older adults lost to follow-up were relatively younger individuals who had left or relocated from the place of the survey. This possible bias due to the loss to follow-up may have affected the study results. Third, the cause of death in the older adults was not collected in this study due to the COVID-19 pandemic restrictions, we could not conduct home visits during the follow-up period in 2020; therefore, we relied on telephone interviews with the family members, local neighborhood committees, or local public security agencies to obtain information on death (yes or no) and the time of death. Thus, the influence of factors other than hypertension and frailty on death cannot be excluded. Finally, the data on blood pressure control were not acquired during the follow-up survey, potentially affecting the findings. Therefore, future studies with further improvements in the questionnaire and inclusion of relevant information to enable a more comprehensive analysis are warranted.
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