Cardiovascular diseases (CVDs) are among the leading causes of morbidity and mortality in women globally [1]. It has been well-recognized that more attention needs to be paid to women’s cardiovascular health due to their poorer outcomes than men, such as more disability, hospitalization and early mortality [2]. This is likely due to the ways CVD risk factors are manifested differently in women (e.g., tobacco use and oral contraceptives, diabetes more hazardous, low socioeconomic status more preponderant as well as depression [3, 4]). Moreover, diagnostic tests are less sensitive in women [5], which is related to the fact that they often have different forms of CVD (e.g., heart failure with preserved ejection fraction, myocardial infarction with non-obstructive coronary arteries, coronary artery dissection and vasospasm) [6], and results in women being diagnosed at later stages of disease than men [5]. Finally, women have a greater burden of some comorbidities than men [6].

Cardiac rehabilitation (CR) is a standardized model of secondary preventive care proven to mitigate this burden. It offers the core components of risk factor management, structured exercise, patient education and psychosocial counselling [7], in a clinical or home-based setting, offered on average over 4 months [8]. It is established that CR participation results in approximately 20% lower mortality and morbidity [9], improved quality of life [10], and is cost-effective [11]. Indeed, CR is recommended for women in clinical practice guidelines [12].

Despite these benefits, CR is under-utilized globally [13], especially in women. Meta-analyses show fewer women than men are referred to CR programs (39% women vs. 49% men) [14]. Even after being referred, women are less likely than men to enroll (38.5% vs. 45.0%) [15] and adhere (64.2% vs. 68.6%) [16] to prescribed sessions. Reasons for women’s under-utilization are multifactorial, including lack of awareness due to less provider endorsement [17], transportation barriers, family obligations and experiencing exercise as tiring or painful, often related to their greater comorbidities [18, 19]. Women also have different CR preferences than men, and many of their preferences are not well-met [20‐22]. For example, women prefer engaging in yoga or dance as forms of exercise rather than using treadmills or cycle ergometers, and they prefer not being rushed, crowded or weighed (the latter two related to desire for privacy).

To address these gender-specific issues, “women-focused” (also termed “gender-tailored” [which we consider to mean that content is adapted to women’s needs and preferences], or “women-only” [meaning the sex composition of CR programming only comprises women] in the literature, among other terms) sessions or full programs have been developed, to attempt to address their barriers and meet their unique needs [23, 24]. Indeed, it is important that in the field we start to better delineate what kind of women-focused CR is being delivered, in terms of how or whether the following characteristics/elements are present (not mutually-exclusive): (a) women-only or mostly women (also considering individually-delivered care [in-person or remote] which is inherently “women-only”, particularly if the healthcare provider(s) is female), (b) content tailored to women (and specifically what and how), and/or (c) some versus the full program is either (a) and/or (b) (e.g., peer support sessions for women, a separate education session for women; Table 1).

Extrapolating from the International Council of Cardiovascular Prevention and Rehabilitation’s (ICCPR) global CR audit, it is estimated there are 686 programs in 45 countries globally offering some form of women-focused programming [25]; this is 41% of countries that have any CR. However, the nature of what is being offered in the “real-world” is not known. Indeed, there has only been one review in this area, which is published only as an abstract. While this work is an advance, they focused only on randomized trials which may not represent what is available in the real-world. They identified 10 trials, with very little detail provided regarding how they are women-focused.

This also leaves questions regarding whether the nature of women-focused CR as delivered can improve utilization [13] (i.e., are women more likely to enrol if these types of models are available? Are they more likely to adhere and complete the programs?), and whether it does better meet women’s needs (e.g., satisfaction). Therefore, the objectives of this systematic review were to investigate the: (1) nature and (2) availability of women-focused CR (e.g., how delivered, tailoring), as well as (3) effects on (a) utilization and (b) satisfaction.

The protocol for this systematic review was registered prospectively on PROSPERO (CRD42020189760). Methods were based on the Cochrane Handbook for Systematic Reviews of Interventions [26]. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines [27].

To our knowledge, this is the first full review investigating the nature of women-focused CR, seeking to establish global availability, common features, access/utilization by women, and satisfaction. Women-focused CR is not widely available; as established, any CR is insufficiently available [85], and in the countries where CR is available, only about 40% have any women-focused CR, with most programs in the countries not offering it. This renders women’s-focused CR highly inaccessible, particularly given less than 1/3 of the programs used any form of technology so could not reach women beyond their locality (if women had the hardware and proclivity to do so, which requires further study).

It could be this limited availability that explains why so few women are aware of women-focused CR (they are hardly aware any CR exists) [19, 87], and hence be aware they can access it [70]. Accessibility is also limited in that it is offered less frequently than traditional mixed-sex CR [21]. This can be particulary problematic for women who are working or have caregiving responsibilities [40], hence offering women-focused programming virtually or asynchronously should be explored.

As summarized in Fig. 2, in about half of studies, the women-focused programming was delivered across the full program, and for the remainder it was a part. In 60% of studies, the CR intervention was for women only, and for the remainder men were involved as well. Only a third had content tailored to women, most commonly education or psychosocial programming. Indeed, about 60% had any psychosocial component, despite desire for this in women [20]. In less than one-fifth of studies were non-traditional forms of exercise offered, again despite this preference by women [20]. This was surprising, and suggests there may be challenges for programs in safely, affordably and/or equitably offering such programming; future research should investigate program-level barriers to offering modes of exercise preferred by women. Finally, given women often desire social interaction [20], it was appropriate most programming was delivered in a group; it may be desirable to do this virtually more commonly in future to augment accessibility for women [78]. It is hoped with this information the CR community can come to consensus on what is considered women-focused CR, with our suggestion that it refers to programs: (a) with at least some CR components with ≥ 50% women, and (b) comprising some form(s) of tailoring to meet women’s needs or preferences (e.g., fulsome psychosocial screening and programming, education content, and/or forms of exercise). Moreover, (c) setting/mode of delivery (i.e., to address women’s common transportation barriers and time constraints related to caregiving responsibilities, respect their preference for more privacy) as well as (d) clinician sex, disciplines represented on the team (e.g., staff with specialization in women and CVD, and in mental health), who deliver patient-centered care for women [88‐90], should also be considered.

Women-focused CR delivery materials were provided in few studies unfortunately, hampering replication. While practical direction on how to develop women-focused CR is needed, some preliminary insights can be gleaned in the literature. Notably, Price et al. applied 6 principles for women’s health to inform their women-only and tailored CR program development [23]. The principles included: empowering women (e.g., encouragement to strengthen personal resources, personal goal setting, empathic environment), that health services are defined broadly and are accessible (e.g., evening classes, cultural sensitivity), that care is collaborative and patient-centered [88‐90], and that innovative and creative approaches are used to meet women’s needs. A narrative review is available on ways in which community and home-based programs could better meet women’s needs, such as offering appealing forms of exercise [91], offering flexible timing and setting, as well as promoting social interactions [24]. With the COVID-19 pandemic, our program delivers weekly women-focused CR sessions, based on our validated patient education program [92‐94], which are freely available online (https://​www.​healtheuniversit​y.​ca/​EN/​CardiacCollege/​Pages/​Women-Learn-Online.​aspx). A recently-published paper presents development and evaluation of a theoretically-based mobile phone-based women-focused CR program using machine learning [78]; preliminary engagement and walking results are promising.

With regard to adherence to these programs once women access them, the findings are mixed (Fig. 2). Overall, results seem to suggest that women are more likely to adhere where programs have some form of tailoring [51], and it may not be the “women-only” aspect that makes a difference [40, 64, 68]. Given women do not like to experience pain or fatigue with exercise, important questions regarding adherence to exercise related to intensity of prescription and exercise mode also require study. There is grossly insufficient data on differences in program completion. Clearly, more research in this area is needed. Interestingly however, a recent study in Sweden found higher mixed-sex CR enrolment among women than men, which they attributed to the fact that it is one of the most gender-equal countries in the world [95], and hence “traditional” CR may also by design better meet women’s needs and preferences. This supports that perhaps CR need not be women-only, but women-tailored.

Unfortunately, only 1 trial with satisfaction data was identified, which assessed a women-only and not gender-tailored program; results were equivocal [21]. Perhaps with this first information regarding what is being offered in women-focused CR, as a CR community we can better standardize women-focused CR feature categorization, and start testing what features are related to greater program satisfaction. Development of a consensus statement on best practices could be useful for the field, until more needed research accrues.

Indeed, this review has raised many questions. Several directions for future research have been identified above. Overall, while it is encouraging that 11 trials have now been done in this area, there is little controlled data on utilization and satisfaction. In addition, while women-focused CR was most often delivered in a clinical setting (which is likely also a function of our inclusion criteria), given home-based CR is inherently “women-only”, more research on ways it can be tailored to better meet women’s needs is needed. Indeed, home-based CR can mitigate some of women’s barriers to utilization, and additionally some women prefer it [22]. Although, home-based CR has been historically less available than traditional CR [96], often likely because it is not as commonly reimbursed [97], with the COVID-19 pandemic there has been a massive shift to online delivery [98], with associated advocacy for coverage, rendering this a more possible avenue in future.

If the evidence does warrant it, what kind of women-focused CR should be scaled up? Based on current knowledge and practice, offering group women-only sessions (not full programs), virtually, in the evenings, tailored to women’s psychosocial and educational needs is likely advisable. Based on the evidence, recommendations regarding dose cannot be made, but leveraging peer support could also meet women’s preferences, while reducing workload on CR staff to deliver such specialized programming. Encouraging women to engage in their preferred exercise modality outside of CR would also be helpful, if programs do not have the capacity to offer it; community resource lists could be developed and shared with women [99]. Exploiting technology could expand reach and contain costs, however patient-centred care is still needed, including close attention to clinical status. Finally, considering context would also be important; culture has an impact on women’s health behaviours and healthcare utilization [100].

While quality of included studies was generally acceptable, caution is necessary when interpreting the results of this review. First, data extraction was not done independently by two researchers. Second, there was no grey literature search, nor were any trial registries searched for potential studies to include. Third, generalizability is limited. Studies were of small sample size, but cardiac conditions more common in women were represented. Given the estimated availability of CR globally [85], studies identified herein stem from approximately 25% of the countries that offer women-focused programming, and 10% of programs [25]. For example, women-focused CR is known to be available in South Africa, Brazil, Chile, Colombia, Paraguay, Uruguay, Afghanistan, Bahrain, Pakistan, Qatar, Belarus, Bosnia, Czech Republic, Turkey, India, Indonesia, mainland China, Malaysia, as well as several European countries [25], yet we do not know what is offered there. Programs in the Eastern Mediterranean in particular were less well-represented in the sample, given the preponderance of women-only programming is delivered there [101]. As women-only CR is culturally-prescribed in the region commonly, more understanding of what is delivered there is urgently needed [100].

In conclusion, half the time women-focused CR involves full programs, including only women, and offering a psychosocial component; as well, in a third of programs content is gender-tailored, and some offer alternative modes of exercise preferred by women. More research is needed to establish the features of women-focused CR that are associated with greater use, satisfaction and outcomes. Given it is not often available, programs may wish to consider offering women-focused sessions virtually, with peer support, addressing women’s unique CVD features and psychosocial needs.