Abstract: We included nine RCTs (1242 participants and 426 surrogate decision-makers) in this review. The meta-analysis included seven studies (876 participants). Participants' mean ages ranged from 62 to 82 years, and 53% to 100% of the studies' participants were men. All included studies took place in the US or the UK. Only one study reported concordance between participants' preferences and end-of-life care, and it enrolled people with heart failure or renal disease. Owing to one study with small sample size, the effects of ACP on concordance between participants' preferences and end-of-life care were uncertain (risk ratio (RR) 1.19, 95% confidence interval (CI) 0.91 to 1.55; participants = 110; studies = 1; very low-quality evidence). It corresponded to an assumed risk of 625 per 1000 participants receiving usual care and a corresponding risk of 744 per 1000 (95% CI 569 to 969) for ACP. There was no evidence of a difference in quality of life between groups (standardised mean difference (SMD) 0.06, 95% CI –0.26 to 0.38; participants = 156; studies = 3; low-quality evidence). However, one study, which was not included in the meta-analysis, showed that the quality of life score improved by 14.86 points in the ACP group compared with 11.80 points in the usual care group. Completion of documentation by medical staff regarding discussions with participants about ACP processes may have increased (RR 1.68. 95% CI 1.23 to 2.29; participants = 92; studies = 2; low-quality evidence). This corresponded to an assumed risk of 489 per 1000 participants with usual care and a corresponding risk of 822 per 1000 (95% CI 602 to 1000) for ACP. One study, which was not included in the meta-analysis, also showed that ACP helped to improve documentation of the ACP process (hazard ratio (HR) 2.87, 95% CI 1.09 to 7.59; participants = 232). Three studies reported that implementation of ACP led to an improvement of participants' depression (SMD –0.58, 95% CI –0.82 to –0.34; participants = 278; studies = 3; low-quality evidence). We were uncertain about the effects of ACP on the quality of communication when compared to the usual care group (MD –0.40, 95% CI –1.61 to 0.81; participants = 9; studies = 1; very low-quality evidence). We also noted an increase in all-cause mortality in the ACP group (RR 1.32, 95% CI 1.04 to 1.67; participants = 795; studies = 5). The studies did not report participants' satisfaction with care/treatment and caregivers' satisfaction with care/treatment. ACP may help to increase documentation by medical staff regarding discussions with participants about ACP processes, and may improve an individual's depression. However, the quality of the evidence about these outcomes was low. The quality of the evidence for each outcome was low to very low due to the small number of studies and participants included in this review. Additionally, the follow-up periods and types of ACP intervention were varied. Therefore, further studies are needed to explore the effects of ACP that consider these differences carefully.

Plain-language summary: In October 2019, we searched for studies assessing the effects of ACP in people with heart failure. We included studies that delivered ACP, which included different methods such as discussion and consideration of individuals' values and preferences on future care and medical treatment compared to usual care strategies. This review included nine studies involving 1242 participants and 426 families/carers. Data from seven studies (876 participants) showed that ACP may increase completion of documentation by medical staff regarding discussions with participants about ACP processes and may improve depression of participants. All-cause mortality might be increased in participants receiving ACP. The effects of ACP on quality of life remained uncertain due to the inclusion of small studies in our meta-analysis. This is further illustrated by the fact that only one study reported whether the received end-of-life care met participants' preferences. Similarly, only one study reported the quality of communication during ACP between participants and healthcare providers. Therefore, the effects of ACP on whether end-of-life care met participants' preferences and on quality of communication were uncertain. None of the studies evaluated satisfaction with care. The quality of evidence was low/very low. Since the number of studies and patients in this review was small, the effects of ACP were limited. There is clearly a need for high-quality evidence from large studies to fully explore the effects of ACP for people with heart failure, in particular their quality of life and whether end-of-life care received after ACP actually meet their preferences.