Although rare disease research is attracting increasing attention, access to healthcare services for caregivers of people with rare diseases has not been extensively studied. The aim of this review was to examine how challenges in accessing health care relate to caregivers’ QOL. To our knowledge, this study is one of the few studies to examine how QOL is viewed through the lens of barriers to accessing healthcare, with a focus on caregivers.

Our first objective was to investigate how caring for a person with a rare disease affects the caregiver’s QOL. Similar to the study by Boettcher et al. on the QOL of parents of children with rare diseases, we found that caregivers had a poorer QOL than healthy controls and caregivers of people with other chronic diseases [14]. The dimensions most affected by caregiving were psychological, physical and social. Caregivers of people with rare diseases were more likely to suffer from depression and anxiety. Our findings are consistent with a review by Pelentsov et al. which found that caregivers of people with rare diseases often feel physically exhausted suffer from sleep disturbances, fatigue, loss of appetite, weight loss, headaches and frequent colds [62]. Due to caregiving, they experience social isolation, loneliness, and dissatisfaction. Participation in social activities may be further limited by the complexity of the person’s condition and their dependence on medical devices [42]. They often feel that their social life is being cut short, that they are losing their freedom and they yearn for more spontaneity [62]. This points to the problem of the lack of respite services for rare diseases, which would allow caregivers to look after themselves and give them a much-needed break.

We found several factors that influence the QOL of caregivers of people with rare diseases. Consistent with previous research by Boettcher et al. and Pelentsov et al., we found that disease severity, patient age, education, gender, and unemployment are important factors influencing QOL [14, 62].

In addition, we identified several new factors that influence the QOL. Sleep quality was found to correlate with QOL. As already stated by Azizi et al., better sleep quality leads to better mental and physical health and vice versa [9]. The patients perceived severity of illness was also a factor influencing caregivers’ QOL. Patients with more severe symptoms needed more support from their caregivers. It is to be expected that the QOL scores reported by caregivers caring for patients with severe illnesses would be lower than those reported by caregivers caring for patients with milder symptoms [20].

The QOL of caregivers was negatively affected if the person they cared for lived in the same house. This could mean that the person being cared for has a more severe form of the disease and needs more care, which may lead to a greater burden on the caregiver and negatively affect their QOL. These findings are consistent with those of Hughes et al. who found that having a family relationship with the care recipient and living with the care recipient were associated with higher levels of objective burden [34].

Furthermore, this could explain a positive relationship between the QOL of the caregiver and the QOL of the person being cared for. Regarding the age of the patient at the disease onset, later disease onset was associated with a lower QOL score for the caregiver. We hypothesise that this result is related to the fact that the rare disease was diagnosed later in life. This finding is similar to that of Lingen et al. who showed that the final diagnosis improves the QOL of parents whose children have a disability [47]. If this is the case, it could also be that caregivers have not received the necessary information, which is an important factor in predicting caregivers’ QOL.

The finding that a later onset of the diseases is associated with a lower QOL can also be explained by Kenny et al.‘s study, which emphasizes the significant impact on the psychological well-being of caregivers and supports the idea that early diagnosis and psychological support are crucial for better adaptation [38].

Increasing duration of care had a negative effect on QOL, both true for daily hourly care and years of care. As Vitaliano et al. emphasise, the somatic condition of caregivers deteriorates with increasing duration of care and makes them more vulnerable to the negative effects of stress [77]. Marital status was also found to have an impact on QOL. Those who were separated or were single had higher scores for feeling overwhelmed than the rest, and single people had a lower QOL, possibly suggesting that single caregivers experience less social and caregiving support and therefore experience greater strain. This could also explain the finding that shared caregiving had a positive effect on improving QOL. These interpretations would be consistent with previous findings that spouses report the lowest burden of caregiving, suggesting that sole caregiving leads to a higher perceived burden [34].

We have found that mothers have a lower QOL compared to fathers, especially in the psychosocial aspects of QOL. In families with disabled children, the traditional division of roles seems to be more pronounced, meaning that the mother takes on the role of caregiver, which is associated with lower well-being. In addition, Gray et al. have shown that illness in the family can have different meanings for men and women. In particular, women are more likely than men to blame themselves for their children’s problems and to see their identity threatened by their children’s illness [29]. As Simon noted, the differences do not just reflect differences in engagement with domestic responsibilities [71]. Even when men and women experience the same conflicts regarding work and family roles, these conflicts are interpreted differently and often to the detriment of women [71].

Our second objective was to examine how access to healthcare services affect caregivers of people with rare diseases. The most frequently cited barrier to accessing healthcare was the difficulty in obtaining a (correct) diagnosis, or the so-called diagnostic odyssey. As Nutt et al. have previously noted, delays in diagnosis and misdiagnosis are a major problem and can lead to many avoidable hospitalisations and inappropriate treatments and tests [58].

Lack of knowledge of medical staff was cited by caregivers as the most common reason for delayed diagnosis, failure of treatment or denial of social services. This led to conflicting information about the diagnosis, misunderstandings [78], or inadequate and missing information [26]. Caregivers reported how difficult it was to find healthcare providers who knew about the disease or had information about treatment. This finding is similar to that of Pelentsov et al. who found that the most frequently cited need of parents of people with rare diseases was the need for information [20]. The lack of information available to parents makes this situation difficult to deal with. Unsurprisingly, parents felt that more information and a better understanding of the disease and what to expect would help them cope with the challenges [17]. If they knew what community health services were available for their child, they could plan more confidently for the future [62]. Caregivers criticise that they refuse to seek help to overcome the limits of their knowledge [35]. The lack of knowledge and treatment options makes caregivers feel that they have to take whatever they can get, even if the treatment is not approved.

Caregivers reported limited collaboration and integration between healthcare providers, prompting them to take on the role of care coordinator to ensure that all healthcare providers have information and the newest results. They must advocate for the person they are caring for has access to much-needed services. As McMullan et al. found, caregivers often have unparalleled personal knowledge of how a rare disease affects the person, although they rarely receive enough practical or medical information to help them in their role [50]. This phenomenon often disrupts the relationship between caregivers and service providers, with caregivers taking on the role of “expert” [17]. The lack of involvement of many different service providers, but particularly the lack of involvement of healthcare providers, could be due to uncertainty about their knowledge of the rare diagnosis and therefor their suitability for treatment [44].

Problems with access to health care services also affect the financial resources of caregivers as they have to pay out of their own pocket. Although the government sometimes provides a small amount in the form of a caregiver allowance, this is not nearly enough to cover the costs of medical treatment and travelling [3]. Raising a disabled child comes with significant additional costs [50], and sometimes caregivers have to reduce their paid working hours or leave the workforce altogether [63]. Another obstacle to the utilisation of care services is the lack of insurance coverage in certain countries because insurance companies are not aware of the rare disease. A study by Gater et al. found that many drugs that are potentially effective for rare diseases are not covered by health insurance companies when used off-label in rare diseases patients [27].

We found that caregivers were able to overcome the barrier to accessing health care by interacting with other caregivers or participating in support groups, which were valuable sources of information.

Our third objective was to examine whether access to health care services affects the QOL of caregivers of people with rare diseases. Similar to our findings, Spencer-Tansley has found factors that affect the QOL, such as caregivers having to assume the role of care coordinator, social isolation, additional financial burden, and lower QOL due to time spent on care [72]. Challenges related to access to and coordination of services negatively impacted mental health. These included: trying to access health services or treatments, how care is coordinated, access to financial support, and access to other supports such as social care or respite care. Thus, we can assume that poor coordination of health services poses many emotional challenges. We found that challenges to accessing health services affect the psychological and social dimensions of QOL. Delays and difficulties in diagnosis and treatment and misdiagnosis were associated with anxiety, frustration, and stress, which affected the psychological dimension.

Even when the disease is diagnosed, finding a competent specialist can be a major problem. The psychological dimension of caregivers’ QOL is also affected, as caregivers face obstacles due to the rarity of the disease and are confronted with the lack of knowledge of healthcare providers. As von der Lippe et al. have found, the lack of knowledge about the rare disease can lead to delayed diagnosis, incorrect treatment or denial of services, all of which can have a negative impact on caregivers’ QOL [78]. Spencer-Tansley has also found that interactions with healthcare providers have a negative impact on mental health [72], and usually lead to stress, frustration and anxiety [17, 63]. Many caregivers report that physicians are confronted with the disease for the first time and have no treatment plan for the disease, that they have no information about possible support groups, and that caregivers usually have more information than providers. Because of this, caregivers feel more responsible and have emotional reactions such as loneliness and insecurity related to the social dimension of QOL. An additional stressor for caregivers is the lack of involvement of healthcare providers. This is also a reason why they feel abandoned and frustrated, which affects both the psychological and social dimensions of QOL. The difficulty of finding a provider may be complicated by the fact that rare diseases can affect multiple organ systems. The number of specialist clinics is limited and they are located in regional centres [4] and can therefore be far away, requiring caregivers to travel long distances. This can place an additional strain on caregivers’ financial resources. Previous studies of thyroid cancer survivors also suggest that financial hardship and negative financial events are associated with poorer QOL [55].

We found that caregivers who connected with other peers online had access to information and emotional support. This is consistent with previous research on breast cancer patients that both social support from other patients can improve QOL [48].

A recurring observation in all countries analysed in this review is the predominant involvement of mothers as primary caregivers. Regardless of cultural context, mothers were the main caregivers, indicating a universal caregiving role. This finding is consistent with the comprehensive cross-cultural study by Weisner and Gallimore, who analysed data from 186 societies worldwide and found that mothers, along with female adult relatives and female children, predominantly assumed the role of primary caregiver for infants and young children [80].

Studies from Germany [13], Spain [12], Australia [56], Canada [49], Brazil [31] and Italy reported lower levels of social support, which may mean that participants from these Western countries, known as more individualistic cultures, may prioritise personal autonomy over collective caregiving tasks or may simply not have the ability to rely on family due to their schedules. This observation is consistent with the findings of Humphrey and Bliuc, who found that while individualistic traits such as personal fulfilment and freedom of expression can enhance psychological well-being, other aspects of individualism such as limited social support, competitiveness and social comparison may contribute to a decline in social relationships and mental health in Western populations in recent decades [37]. This could also explain the reliance on formal care services instead of family support mentioned in the Australian (Mori et al., 2017) and Canadian [22] studies could indicate cultural norms or societal structures that favour formalised care services over informal support networks, or simply the availability of these services that have yet to be developed in other countries.

In contrast, Nigerian caregivers reported a medium to high levels of perceived social support, indicating a more supportive social environment for caregivers in this cultural context [1]. Cultural factors such as strong family ties, community support networks or cultural norms that emphasise collective responsibility for caregiving may contribute to the higher levels of social support observed among Nigerian caregivers. In Nigeria, as in many other African countries, social support from the extended family is taken so much for granted that it is commonly referred to as the “African extended family system” [23].

This review compiled detailed information on the impact of caring for people with rare diseases on caregivers’ QOL, with a particular focus on their experiences of accessing healthcare services for the people with rare diseases they care for. It is clear that, caregivers of people with rare diseases face many unique issues and should be better supported to alleviate their burden. This study shows that healthcare systems need new strategies, as the current healthcare systems often leave it up to caregivers to become rare disease experts and advocate for to access to treatment and help. This responsibility should not be left in the hands of caregivers but, needs to be addressed systematically. By highlighting the impact of barriers to accessing healthcare services, we wanted to encourage policy makers and care providers to develop new strategies to support caregivers and improve health outcomes.

Furthermore, the consistency of our scoping review with previous studies by Boettcher et al. and Pelentsov et al. [14, 62] emphasises the consistency of the challenges faced by caregivers in different contexts. While Pelentsov et al. focused primarily on the needs of parents of children with rare diseases, the parallels that emerge from their findings are strongly consistent with the challenges we identified in our study. This consistency highlights the universal nature of the challenges of caring for people with rare diseases and emphasises the need for comprehensive support systems tailored to the specific needs of carers around the world.

Our study has some potential limitations. First, the search strategy was limited to English-language studies. Therefore, there may be other literature that is equally relevant to the area of QOL and access to health services but may have been overlooked. Although the inclusion of articles in other languages would likely increase the selection of relevant articles, the scientific world tends to publish as much as possible in a single (English) language. The selection of articles was primarily made by one reviewer, but in cases of doubt an independent review was conducted. Also, due to the search strategy, we may have excluded many rare diseases, so QOL and access to healthcare may not be well represented for all diseases. However, this limitation was addressed by a manual search of the reference lists of included studies, which allowed us to access many studies published under other search terms.

We found that in most of the studies we examined, the voices of female caregivers were present. Less is known about the experiences and challenges faced by male caregivers. The literature often emphasises the perspective of female caregivers, so we do not understand how male carers manage their role, cope with stress and interact with healthcare systems. We do not assume that caregivers are homogeneous. Therefore, caregiving and its relationship to gender and coping must be adequately assessed to provide an accurate description of the differences between men and women in relation to this phenomenon.

The included studies that used a qualitative design utilised purposive sampling, i.e., recruitment of participants focused on sources where caregivers of children with rare diseases were active, such as hospitals and rare disease support groups. This meant that participation was limited to those who had more connections to services and peer support. Therefore, it is possible that other perspectives and experiences of services were not well represented.

On the other hand, the study also has some important strengths. As far as we know, this is one of the few studies that examines access to health services among rare disease caregivers, focuses on caregivers’ quality of life, and examines how QOL is affected through the lens of barriers to accessing healthcare. This review also includes all known research in selected bibliographic databases. The strengths of this literature review lie in its methodological and systematic approach, that explores the experiences of caregivers of people living with rare diseases from both qualitative and quantitative perspectives. The review provides insights into the complexities of caring for people with rare diseases and highlight many areas for improvement in the future to enable better planning of health care and other services.

These findings may help to understand the problems associated with caring for people with rare diseases. This information could help service providers to better understand and help caregivers of people with rare diseases to appropriate support. It can help primary care physicians by providing information about the needs of caregivers, such as the need for continuity in dealing with diagnostic uncertainty and the provision of an empowering and collaborative approach.

The review emphasises the importance of prioritising carers of people living with rare diseases in Slovenia, as they face very different challenges to carers of older people, who already receive more attention [15, 60].

Future research should focus on examining cultural or regional differences in the impact of rare diseases on caregiver QOL and access to healthcare. Further research could focus on examining the impact of rare diseases on caregiver’s QOL with treatable diseases comapred to those without treatment. It might also be interesting to examine at how the needs of caregivers change over time. Further research should also consider the use of longitudinal studies and larger samples to investigate the impact of care on QOL. Studies such as the one by Rotar-Pavlič et al. study on the experiences and feelings of informal caregivers of elderly in Slovenia and the challenges and difficulties they face in the society [60] would also be welcome.