This study identified common experiences of patients with rare diseases, from symptoms through to diagnosis, and the results have been used to inform a series of red flags that can aid the recognition of when a patient may have a rare disease in non-specialist settings. As part of the questionnaire, responders were asked to propose three red flags of rare disease (Fig. 4), however, all questionnaire responses were considered collectively to determine the following seven red flags of rare diseases: multi-system involvement (3 or more); genetic inheritance pattern; continued presentation throughout childhood and adulthood; difficulties at school, especially relating to absences, difficulty participating in physical education and experiences of bullying or social isolation; multiple specialist referrals; extended period with unexplained symptoms; and misdiagnosis. These red flags include physical and psychosocial characteristics in addition to considering patients’ engagement and experiences with healthcare providers. Their diversity reflects the multiplicity of ways in which rare diseases impact patients’ lives and the many different settings in which they may present. The majority of red flags identified are of relevance to clinical and/or education environments which highlights the role of clinicians and educators in the recognition of red flags, and subsequent diagnosis of rare disease. Adopting the red flags concept in clinical practice would require clinicians to adopt a holistic view of the patient’s experiences and symptoms; the physical, psychosocial and healthcare provider interactions should be considered in combination, and the appearance of many, varied red flags may be an indicator of rare disease in itself.

For each red flag identified, recommendations for clinical practice and/or education settings are presented in Table 2. As primary care services function as patients’ first point of contact with healthcare services, they present an ideal clinical environment for the implementation of a diagnostic aid for rare disease and, crucially, they offer clinicians the opportunity to gain a holistic view of the patient’s wellbeing. It is suggested that clinicians adopt a holistic approach to assessment that considers the patient’s history, including family history, and be alert towards the common systems implicated in rare diseases. Additionally, clinicians should maintain awareness that rare diseases can present in both childhood and adulthood, and consider how patients’ interactions with healthcare systems may be indicative of rare disease, for example, if a patient has received several misdiagnoses. It is also suggested that clinicians are informed of the psychosocial red flags of rare disease in addition to physical red flags.

Education settings are proposed to have a role in identifying individuals presenting with rare disease therefore it is suggested that awareness of rare diseases should be raised amongst teachers and other educators. For example, the physical and psychosocial red flags of rare disease, behavioural difficulties indicating rare disease and how to support parents to seek clinical assessment should be explored. This is further supported by a previous survey of educators in Spain, where approximately 28% and 48% answered “Not at all” for the questions “I know the warning signs a student with a possible rare disease may present” and “I know how to clinically diagnose a rare disease”, respectively [18].

Given that 71.6% of respondents identified their respective rare disease to affect three or more body parts or systems, it is suggested that multi-system involvement should be considered as a red flag of rare disease. In addition, the large number of different medical specialities proposed to be primary medical specialities (n = 18), and the inclusion of allied healthcare professions within this, highlights the importance of thorough history taking and the need to consider the wide range of potential symptoms and medical specialities that may be relevant. Additionally, it is notable that the second most common ‘discipline’ identified was multiple specialist teams, which indicates that rare diseases typically cause varied physical and psychosocial impacts. Over a third of respondents reported their rare disease to be invisible, which further emphasises the variability in rare disease presentation and is important to consider since ‘invisible’ diseases are typically more difficult to identify, reinforcing the importance of thorough history taking and understanding the patient’s experience. Despite the importance of taking a thorough patient history described here, it should be acknowledged that this is reliant on patients disclosing all relevant information to their healthcare provider, which may in itself become a barrier to diagnosis. This underlines the importance of effective interactions between patients and healthcare professionals, including education of the patient, psychological support and trust-building, to aid in the diagnosis of rare diseases [19].

The importance of considering patient history is also emphasised by the results for questions concerning disease presentation and problems in childhood. Over 75% of respondents reported that patients experienced difficulties at school, the most common issues being difficulty participating in physical education, learning disabilities and regular/prolonged absences from school; observation of these factors could encourage clinicians to consider the possibility of a rare disease in a young patient. Furthermore, although current literature reports that approximately 70% of rare diseases present exclusively in childhood, in this analysis, over half of respondents reported that disease can present in both childhood and adulthood [2]. Therefore, clinicians should maintain awareness that rare diseases can present in adulthood or may remain undiagnosed until adulthood. However, given that the results for this question vary from the literature, further study should be conducted to understand whether specific rare diseases present exclusively in childhood and how awareness of this could be used to aid diagnosis in clinical settings.

Respondents also reported common experiences when interacting with healthcare providers; over 75% of respondents reported that patients experience three or more referrals, which implies patients are frequently referred to specialists who were unable to determine an appropriate diagnosis. Furthermore, whilst the varied results indicate it is difficult to determine an average time to diagnosis, patients typically experience a delayed diagnosis, with over 20% of respondents reporting a time to diagnosis of over five years. Given the well-established ‘diagnostic odyssey’ associated with rare diseases [20], this is an unsurprising but nevertheless critical result which demonstrates the immense challenge of timely diagnosis. Delayed diagnosis can also be compounded by misdiagnoses. In this study, over 70% of respondents reported it was typical for patients to be labelled with an alternative diagnosis which poses a risk to patient safety given that misdiagnoses can lead to the premature ending of the diagnostic work-up, preventing further assessment or evaluation for alternative aetiology. These findings are in agreement with a report for the Department of Health and Social Care which postulates that, on average, a patient may see five doctors and have three misdiagnoses prior to formal diagnosis [20]. However, it is important to consider alternative explanations for the large proportion of patients reporting misdiagnoses; it may be that respondents have misinterpreted clinical investigations conducted to rule out common causes of their symptoms to be misdiagnoses and further work is needed to understand patient group perceptions of misdiagnosis.

Reported misdiagnoses varied widely and included both physical and mental health conditions across all specialities and body systems. Epilepsy and arthritis were amongst the most common misdiagnoses reported; however, as evidenced by the disease processes of adrenoleukodystrophy and alkaptonuria, these conditions can be secondary processes, or part of a syndrome, and do not necessarily constitute the final diagnosis [21, 22]. This highlights how secondary disease processes can be incorrectly diagnosed as primary conditions and have the potential to exacerbate the rates of misdiagnosis amongst patients with rare disease. Additionally, it is notable that the most common misdiagnosis reported was isolated mental health problems (7.7% of all misdiagnosis reported) which may lead to premature ending to the diagnostic work-up, allowing disease progression and potential iatrogenic development of mental health disorders as a result of their physical health burden. However, as described in previous reports published by Rare Disease UK and Genetic Alliance UK, receiving a mental health diagnosis in the context of an undiagnosed rare disease may be distressing to a patient since they may be given the impression that their clinician perceives their symptoms as fictitious [23, 24]; it is therefore important that clinicians have an awareness of the psychosocial burden of rare diseases. Whilst misdiagnosis is a challenging and complex issue to overcome in clinical practice, there is a role for increasing awareness of the rates of misdiagnosis and common misdiagnoses amongst clinicians.

Given that this study was designed as a service evaluation, the red flags identified do not present generalisable findings but rather present information that can be used to inform decision-making in clinical settings. The authors acknowledge that the efficacy of implementing these actions has not been tested and suggest that the findings of this study are used to inform a diagnostic framework or tool, designed to optimise early recognition of rare disease, that can be implemented and tested in primary care settings.

Strengths of this study include the range of rare disease groups sampled; the study methodology was designed to obtain a broad range of rare diseases, so the results were reflective of the collective experiences of rare disease patients, as opposed to one group of rare disease patients. In total, 79 different rare diseases were captured by the survey and whilst this only represents a small proportion of all rare diseases, it was sufficiently broad to capture common experiences across different rare disease groups. Furthermore, the restriction to only include rare disease groups based in the UK ensured the results were representative of the experiences of rare disease patients in the UK and therefore, applicable to the UK healthcare setting. The use of qualitative analysis enabled deeper insights into the respondents’ narrative accounts to be explored, which was a key objective of the study.

Limitations of the study include the sampling methodology employed which was non-random and therefore subject to bias. The sample also included a mix of patient representatives and healthcare professionals, which may contribute to some level of bias in the study findings. However, it should be noted that this approach was taken in order to gain a holistic view of patient experiences with rare disease diagnosis. Furthermore, although the questionnaire clearly described its objective to identify the common experiences of rare disease patients, respondents may be inclined to answer questions based on their own personal experiences, rather than shared, collective experiences, which would limit the utility of the results for informing a diagnostic tool. Regarding the analysis, there is a level of subjectivity involved in thematic analysis and therefore there was potential for the analysts’ personal experiences/bias to influence the results of the analysis. Lastly, we acknowledge the time interval between collection of the data in 2018 and publication of these results and encourage healthcare professionals to take these findings together with their lived experiences and in the context of their current practice.

Given the role of the rare disease community in generating these results and the importance of transparent information sharing, especially regarding the ‘diagnostic odyssey’, it is important that these results are disseminated to the rare disease community and wider clinical audiences. Given that the utility of the red flags proposed in this publication has not been tested in clinical practice, further research should be conducted to understand the efficacy of the red flags concept in diagnosing rare diseases in primary care settings.