Study selection and search results

The results of the evidence selection phase are illustrated in a PRISMA 2020 flow diagram [29] as Fig. 1.

Study characteristics

Of the 19 articles conducted in either community or nursing home settings, four articles were from the USA, three articles were from Australia, two articles were from mainland China, two were from Hong Kong SAR, and there was one article each from England, Switzerland, Canada, Singapore, Japan, Netherlands, Belgium, and Korea. Of these, three were qualitative research articles, 13 were quantitative research articles, two were mixed-method articles, and one article was a review. The review of the literature revealed that ACP is more commonly practiced in Western countries, such as the USA, Australia, and European countries. This is consistent with the findings of Martin et al. [30]. However, interest in this topic is increasing in the Asian cultural context, particularly in China, Korea, Singapore and Japan, where they have successfully encouraged people to use or develop ACP in the form of legislation or recommendations [31].

Synthesis of resultsThe extent of ACP readiness among community-dwelling older adults

ACP readiness can be defined as an individual’s willingness to actively participate in conversations concerning one’s values and preferences with both family members and HCPs about engaging in ACP [14, 32]. It assesses a person’s behavioral tendency and willingness to participate in the process at the individual level [33]. According to the knowledge-attitude-behavior theory, an individual’s knowledge directly influences their attitudes, consequently impacting their willingness to participate in the behavior (see Fig. 2) [34, 35]. Knowledge serves as an initial step in the process of readiness for action [36, 37], while attitude stands as one of the most significant indicators used to predict and explain intentions and behaviors [38]. Therefore, two subthemes, (1) knowledge about ACP and (2) attitudes toward ACP, were further described to illustrate ACP readiness among community-dwelling older adults.

Fig. 2

The knowledge-attitude-behavior model

Knowledge about ACP

This review revealed that the knowledge about ACP among older adults across all settings was limited. For instance, a study in the USA involving 921 participants aged 55 years and older revealed that only 11.9% answered all ACP-related items correctly [39]. In Australia, among 229 older adults, only 24% of participants were aware of advance directives (ADs) [12]. A survey of 2,125 older residents in Switzerland showed that 50% of participants lacked the knowledge about ACP dispositions [40]. Similarly, in a survey conducted in Japan, Korea, Hong Kong SAR, and China, only 30% of respondents had knowledge about ACP or ADs [17]. The low level of knowledge about ACP was also observed among older Chinese migrants [38, 41]. This is even more evident in mainland China, where a cross-sectional survey in Zhengzhou City showed that 92.7% of older residents in the community had never heard of ACP [42].

Attitude toward ACP

Despite the initial low awareness of ACP, older adults displayed an increased willingness to engage in ACP after being informed about its purpose and benefits. For instance, a study conducted in Korea found that 80% of community-dwelling older adults agreed with the need for an AD after receiving explanations [31]. Similarly, in Switzerland, a notable portion of older adults expressed openness to completing ACP upon becoming aware of its opportunities [40]. In Belgium, interviews with 25 older adults revealed that despite initial lack of knowledge, they showed positive inclination towards ACP following detailed explanations [43]. In Hong Kong, a survey involving 286 older adults demonstrated that, despite their lack of knowledge about ACP, 42.3% of participants expressed a preference for ACP after receiving an explanation [44]. In mainland China, after the investigators explained the related concepts, the attitude toward ACP by older adults in the community was found to be improved [45], aligning with the findings of Zhu et al. [42].

Influencing factors toward ACP readiness among community-dwelling older adults

Implementing ACP among older adults in the community is beneficial in preserving their autonomy, preventing harm, and ensuring equitable treatment [44]. However, various factors can impede individuals’ decision-making processes regarding ACP, including individual demographic characteristics (e.g., age, cultural, and health-related factors), HCP factors, and family support [2]. This review will discuss both intrinsic and extrinsic influencing factors, depending on their origin. Table 2 summarizes the themes concerning the influencing factors on ACP readiness.

Table 2 A summary of the themes concerning influencing factors on ACP readinessIntrinsic influencing factors

Three subthemes regarding intrinsic influencing factors were derived from the reviewed studies: (1) sociodemographic characteristics, (2) psychological factors, and (3) family relationships.

Sociodemographic characteristics

In this literature review, we found that age, education level, economic status, health status, acute care experience, and cultural background significantly affect ACP readiness. With age, gradual physiological deterioration, and declining health, older adults tend to think more about issues related to death and are willing to discuss EOL care [17, 46]. However, among older adults, those who are younger are more likely to prefer ACP. Xu et al. [44] found that individuals in age groups 65–74 and 75–84 years may be more receptive to new information and knowledge compared to those aged 85 years and older. This is similar to the findings of Musa et al. [47], who established that younger older adults are more inclined to participate in ACP. Additionally, education level substantially impacts ACP readiness. Studies have shown that older adults with higher levels of education tend to have greater knowledge of and access to health information, which allows them to better understand changes in their condition and prognosis. They are also more aware of the importance of ACP and are, therefore, more willing to participate in it [40, 44]. Furthermore, the level of economic status is found to be inversely related to ACP readiness, with older adults with low economic status being more supportive of ACP [31, 48]. This is possibly due to their uncertainty about the course of their illness, anxiety about their financial ability to afford treatment, and an expectation that ACP will determine their future care.

Health-related factors, including health status and acute care experience, have previously been identified as factors influencing ACP readiness [41, 45]. Older adults with poor health were more willing to participate in ACP [31, 43,44,45]. This may be related to the fact that older people in poor health, who have long coexisted with a variety of diseases, are characterized by a high mortality rate, a high disability rate, and a poor prognosis. Those who have been enduring significant physical and psychological hardships for an extended period tend to have a lot of doubts about their future physical well-being, as well as a sense of fear and anxiety about what they may experience as they approach the end of their lives. This is why ACP has become even more important for them. Older adults who have been exposed to seriously ill patients and experienced critical first aid are more likely to consider ACP [45], because those who experience these events may develop fear and refuse emergency measures or life-sustaining treatment (LST), influencing their own views on hospice care and the completion of ACP [31, 42, 49].

Awareness levels, attitudes, and the completion of ACP can vary significantly within different cultural contexts [12, 17]. Western countries emphasize patient autonomy, informed decision-making, and truth-telling, which is consistent with the foundation of ACP [44], whereas this idea is contrary to the Confucian culture, where death is considered a taboo topic, and older adults avoid topics related to death. At the same time, Confucian culture emphasizes familism, especially when it comes to EOL care decisions, where family collectivism is valued over patient autonomy [45]. Within this cultural context, children will be motivated by filial piety beliefs and make efforts to prolong the lives of their parents, which may sometimes be in opposition to their parents’ wishes [50]. Even among Western countries, there are differences in the specific ways in which ACP is carried out. For example, individual rights and autonomy are paramount in North America, while in Europe, the focus is more on the balance between the principles of autonomy, beneficence, and justice [46]. Thus, unlike respondents in Canada or the USA who managed to document their ACP, respondents in the Netherlands and the UK preferred to participate in the ACP program informally, such as by discussing it with family members or physicians [46].

Psychological factors

Psychological factors, such as death anxiety or mistrust in HCPs, exert considerable influence on ACP readiness. Death anxiety may lead older adults to avoid discussions about EOL matters, hindering their participation in ACP [43, 51]. Paradoxically, engagement in ACP has been linked to a reduction in death anxiety and an enhancement of QOL for older adults [45, 51]. Research indicates that older adults completing ACP report lower death anxiety levels and a greater sense of peace compared to those who abstain from ACP [52]. However, initiating ACP discussions abruptly at an older adult’s EOL, without adequate preparation, may trigger negative emotions associated with death, contributing to heightened death anxiety [10]. This underscores the critical importance of timing in initiating ACP discussions, directly impacting the success of ACP [53]. Studies reveal that older adults are more likely to discuss ACP with family members rather than HCPs, citing a lack of trust in HCPs [25, 38, 47]. This distrust stemmed from a belief that engaging in ACP might prompt HCPs to prematurely cease treatment or make medical decisions contrary to their preferences, leading to a reluctance to participate [39, 47]. Additionally, older adults perceived ACP-related issues as sensitive and expressed discomfort discussing them with HCPs due to a perceived lack of sensitivity from them [54]. Further, doubts arose about healthcare aligning with older adults’ ACP due to a lack of follow-ups as well as HCPs’ limited knowledge about ACP [51].

Family relationships

Family relationships can be assessed through two key dimensions: family cohesion and family conflict [38, 50]. Family cohesion is a crucial positive aspect of older adults’ relations with their families [55]. On the other hand, family conflict represents as a risk factor that negatively affects family relationships [56]. Previous studies have shown that high family cohesion is associated with a more positive attitude toward family involvement in discussing EOL care planning and encouraging older adults to participate in ACP [38, 43, 44]. There was also a study that showed that family cohesion had no significant relationship with the contemplation or discussion of ACP, while family conflict can serve as an indicator of a heightened necessity for engaging in ACP [50]. This might be attributed to older adults weighing the potential benefits and burdens of participating in ACP. Despite their positive attitudes toward ACP, they may hesitate to discuss it with their families because of the emotional burden the discussions put upon them. Similarly, systematic reviews have found that older adults may not engage in ACP if they are highly dependent on their families for decision-making [47]. Given the diversity in the research findings, further exploration is needed to clarify the relationship between family relationships and participation in ACP.

Extrinsic influencing factors regarding ACP readiness

Extrinsic factors were explored in many studies that impacted older adults’ decision to discuss their care management, as explained by the two subthemes: (1) HCP attitudes and experience; and (2) policies and laws.

HCP attitudes and experience with ACP

HCPs with negative attitude toward and lack experience in ACP may diminish the willingness of older adults to engage in ACP [51]. Surveys conducted among both HCPs and patients in primary care settings have indicated that discussions should be initiated by HCPs and should involve repetitive interactions with patients [25, 40]. However, in both primary care and hospital settings, HCPs tend to avoid the topic of EOL care and exhibit reluctance in engaging in ACP conversations [25]. This reluctance may stem from fears of legal repercussions for discontinuing LST [31] and concerns about potentially exacerbating negative emotions in patients, which could impede older adults’ access to ACP [46, 57]. Moreover, HCPs often lack experience with ACP. Only 5.9% of individuals aged 65 and older have had an ACP discussion with their HCPs [40]. In Korea, only about one-fifth of doctors had experience in helping patients who had completed an AD [31]. The deficiency in knowledge and experience regarding ACP further contributes to negative attitudes among HCPs toward ACP [2].

Policy and law

Legislative support is crucial for ensuring effective implementation of ACP [58, 59]. Research indicates that the introduction of relevant policies and laws positively influences older adults’ attitudes toward ACP. The earlier these policies and laws are enacted, the sooner ACP prevalence increases [44]. For instance, in the USA, the Patient Self-Determination Act (PDSA) came into effect in 1990, affirming patients’ rights to accept or refuse medical or surgical treatment [31]. In Switzerland, several states passed ACP laws in the late 1990s [40], and since 2002, ACP has been implemented in various settings in Victoria, Australia [12]. The Japanese Ministry of Health, Labor, and Welfare revised guidelines for EOL decision-making in 2018 [59]. South Korea recognized the legal validity of ACP and ADs through legislation in 2016 [60], and Hong Kong developed ACP guidelines in 2010 [17]. The slow development of ACP in mainland China also has a lot to do with the fact that China has not yet enacted specific national legislation that comprehensively defines ACP [42]. ACP management has not been fully integrated into the healthcare system, resulting in inadequate coverage for the community population [42].