Unexpected gaps in knowledge of familial hypercholesterolaemia among Dutch general practitioners

Participants who had incompletely filled out questionnaires or submitted duplicates were excluded from the analysis. In addition, respondents not currently practicing as GPs were excluded. Upon reasonable request, the data that support the findings of this study are available from the corresponding author.

The study participants were presented an online survey based on a standardised questionnaire, which was previously developed and used in the ‘Ten Countries Study’ [13]. The ‘Ten Countries Study’ is a multinational research initiative that involved the participation of > 1000 primary care physicians, who completed a survey aimed at assessing their knowledge of FH and identifying gaps in their management of the disorder. The study enrolled primary care physicians from 10 countries and regions in the Asia-Pacific, including Australia, China, Hong Kong, Japan, Malaysia, Philippines, South Korea, Taiwan, and Vietnam, using the UK as the reference group. The survey was translated into Dutch and underwent several modifications and adaptations tailored to the current study (see Table S1 in Electronic Supplementary Material).

A total of 17 questions pertaining to FH were included in the adapted questionnaire, which were categorised into 3 sections: (1) awareness, (2) knowledge, and (3) preference, practice, and screening. The awareness-related questions encompassed various aspects, such as familiarity with the disorder itself and FH management guidelines. The level of familiarity with FH was evaluated by having the GPs self-rate their familiarity using a scale ranging from 1 to 7. This self-rating scale followed the approach outlined in the ‘Ten Countries Study’, where a score > 4 denoted above-average familiarity. To evaluate the GPs’ knowledge of FH, 8 questions covered areas such as the FH definition, hereditary pattern, prevalence and CVD risk. Lastly, the survey included 6 questions to assess GPs’ practices concerning FH.

In light of evolving guidelines after the development of the questionnaire, treatment-related questions were excluded from the survey. Furthermore, given the contemporary estimate of FH prevalence of 1:250, as opposed to the previous rough estimate of 1:500, this aspect was modified in the current study. Detailed information on the full questionnaire and modifications of the questionnaire used in the ‘Ten Countries Study’ can be found in Table S1 in the Electronic Supplementary Material.

A total of 246 respondents successfully completed the questionnaire, 25 of whom were excluded due to their lack of current engagement as practicing GP. The final analysis therefore comprised 221 GPs, whose demographic characteristics are presented in Tab. 1. Among the respondents, 122 (55.2%) were practicing in rural areas, while the remaining 99 (44.8%) practiced in metropolitan areas. In terms of practice setting, 105 GPs (47.5%) were affiliated with a group practice, while 75 (33.9%) worked in a duo practice and 41 (18.6%) in a solo practice. The median years of experience as a GP was 15.0 (IQR: 7.0–22.0), and the median number of diagnosed FH patients in the practice was 5.0 (IQR: 3.0–10.0).

The survey responses are shown in Tab. 2. In the present study, 138 GPs (62.4%) rated their familiarity as above average (i.e. score > 4/7). Moreover, 202 (91.4%) reported being familiar with the FH treatment and referral guidelines and 122 GPs (55.2%) answered they were familiar with specialised health institutes for lipid disorders.

GPs with ≥ 15 years of professional experience rated their familiarity with FH significantly more often as ‘above average’ compared with those with < 15 years of experience (OR 1.91; 95% CI: 1.11–3.31; p = 0.02) and were more familiar with specialised lipid institutes (OR: 2.86; 95% CI: 1.66–4.96; p < 0.001). Moreover, GPs with ≥ 5 FH patients in their practices also rated their familiarity with FH significantly more often as ‘above average’ compared with those with < 5 FH patients (OR: 2.17; 95% CI: 1.17–4.10; p = 0.01).

General knowledge of FH among GPs was evaluated using 8 questions incorporated in the survey (Tab. 2, and see Table S1 in Electronic Supplementary Material). Of the GPs, 185 (83.7%) correctly identified the FH definition, while 194 (87.8%) correctly recognised the characteristic FH lipid profile. The correct prevalence of FH, its inheritance pattern, and the risk of atherosclerotic CVD (ASCVD) associated with FH were identified by 43 (19.5%), 123 (55.7%) and 30 GPs (13.6%), respectively. Of the participants, 118 (53.4%) underestimated the actual ASCVD risk associated with FH. The correct age for premature ASCVD in men and women was identified by 28 (12.7%) and 61 GPs (27.6%), respectively. The mean age given for premature ASCVD in women was 56.2 ± 8.8 years and 52.0 ± 8.9 years in men. Of the GPs, 80 (36.2%) perceived ASCVD as occurring prematurely in women at an age younger than that specified in national guidelines (< 60 years), while 45% regarded ASCVD as premature in men at a younger age than that outlined in the national guidelines (< 55 years).

Of the respondents, 183 (82.8%) regarded their own profession as the most suitable for early detection and cascade screening of FH and only 105 (47.4%) referred their FH patients to a specialised health institute for lipid disorders. Regarding FH management, 156 respondents (70.6%) screened lipid profiles in first-degree relatives of FH patients and 194 (87.8%) screened patients with premature coronary artery disease (CAD) for a family history of CAD. Furthermore, 114 GPs (51.8%) initiated lipid profile screening in adolescents aged 13–18 years in families with premature CAD. FH screening in children before the age of 13 was undertaken by 45 (20.4%) of the participating GPs. Implementation of interpretative commenting on laboratory lipid profiles, which alerts physicians to the potential presence of FH, was endorsed by 183 GPs (82.8%), thereby acknowledging its potential to enhance identification of FH in primary care settings.

Dutch GPs rated their familiarity with FH higher compared with primary care physicians from the UK (OR: 2.52; 95% CI: 1.53–4.27) (Fig. 2a). Among the countries participating in the ‘Ten Countries Study’, the percentage of self-perceived familiarity with FH rated as above average was < 50% [13], whereas it was 62.4% in the Netherlands. A similar difference was observed for self-perceived awareness of FH guidelines (OR: 6.38; 95% CI: 3.35–12.48) (Fig. 2b). With respect to the FH-related knowledge questions pertaining to the definition, typical lipid profile, prevalence, hereditary pattern, and associated CVD risk, Dutch GPs exhibited comparable scores as the primary care physicians in the UK (OR: 0.66; 95% CI: 0.29–1.40; OR: 0.89; 95% CI: 0.38–1.95; OR: 0.58; 95% CI: 0.33–1.04; OR: 1.23; 95% CI: 0.74–2.02; and OR: 1.00; 95% CI: 0.49–2.15, respectively) (Fig. 3). Comparable proportions of GPs conducted screenings for family history of CAD in patients with premature CAD in the ‘Ten Countries Study’ and the Netherlands (Fig. 4a). Moreover, Dutch GPs performed routine family screening in FH patients at a frequency comparable to that of primary care physicians in the UK (OR: 0.91; 95% CI: 0.51–1.58) (Fig. 4b).

The current study sheds light on the suboptimal knowledge of FH among Dutch GPs. These findings align with previous questionnaire studies conducted in the countries participating in the ‘Ten Countries Study’, as well as the US [13, 14, 18, 19]. A consistent pattern observed in these studies was that the primary care physicians perceive themselves as the most appropriate healthcare providers for managing FH, despite their suboptimal awareness of the guidelines and their limited knowledge of its prevalence and the diagnostic characteristics. Only a small proportion of GPs in the current study correctly identified the FH prevalence (19.5%) and heritability (55.7%), which are key factors for recognising potential FH cases. Most GPs either underestimated the true prevalence of FH, perceiving it to be less common than it actually is, or indicated uncertainty regarding the prevalence. In addition, only 13.6% correctly identified the CVD risk associated with FH, while the vast majority (53.4%) underestimated this risk. Moreover, GPs perceived the threshold for premature CVD onset to be 4 years earlier for women and 3 years earlier for men compared with the defined age thresholds outlined in the guidelines, although this difference in perception may not necessarily translate into a significant impact on clinical outcomes or management strategies. Nonetheless, the limited understanding of FH prevalence and heritability and the associated CVD risk poses a significant obstacle to effective FH screening and can further contribute to the problem of FH underdiagnosis and undertreatment [4]. These findings emphasise the necessity of increased awareness among GPs to ensure accurate recognition of FH cases.

Guidelines have recommended that early identification and management of FH patients take place in a primary care setting, as primary care plays a critical role in cascade screening and achievement of long-term treatment adherence [1, 20]. Indeed, most GPs acknowledged their suitability as healthcare provider to detect FH and were open to interventions that improve FH identification, including interpretative comments accompanying laboratory results to alert them to the likelihood of FH. Moreover, most GPs (~70%) expressed their intentions to screen lipid profiles in close relatives once an FH patient was identified. This holds substantial importance, as cascade screening has been established as a highly cost-effective mean of identifying new cases of FH [21]. Nonetheless, the findings revealed a disparity between the self-perceived familiarity and the actual knowledge of FH among Dutch GPs.

Therefore, it is imperative to develop strategies that address these knowledge gaps and enhance FH awareness among GPs. These might include a more pronounced integration of FH education into GP training curricula, dissemination of FH-related information through frequently attended GP conferences and webinars, and enhanced collaboration with lipid specialists. Focusing on GPs in the early stages of their career may especially be effective, considering that GPs with more professional experience achieved significantly higher knowledge scores, possibly due to exposure these more experienced GPs had to the nationwide cascade screening programme, which was discontinued in 2013. For GPs less experienced in FH management, more referrals to specialised lipid clinics and increased interaction with experts are essential until adequate knowledge is acquired.

Furthermore, the issue of suboptimal understanding of FH in primary care extends beyond the borders of the Netherlands and rather encompasses an international challenge. Therefore, exploring international collaboration to design effective educational programmes targeting knowledge barriers may offer a valuable approach to overcome global key barriers in FH care implementation. These educational programmes, preferably developed in collaboration with GPs, should be embedded in implementation science frameworks [22, 23]. Implementation science provides a structured method to integrate recommended strategies and guidelines into practice, focusing on identifying and addressing gaps between current practice and evidence-based recommendations. By leveraging these frameworks, which focus on factors that can create resistance to health system reform, such as resource constraints and computability with existing workflows, tailored interventions can be systematically designed, tested and implemented, which can ultimately improve the detection and management of FH [23].

The current study has several limitations. First, the participants were opportunistically selected, potentially leading to a bias if GPs with a higher affinity towards the subject matter were more likely to respond. However, this would imply an overestimation of the participants’ performance, further emphasising the need for additional efforts to enhance FH knowledge and awareness among Dutch GPs. In addition, substantial efforts were undertaken to ensure the demographic representation of the sample concerning the GP population in the Netherlands.

Second, it is important to note that healthcare systems vary across countries. Particularly, the delivery of primary care may involve various types of physicians in different countries, whereas in the Netherlands, this role is exclusively fulfilled by GPs. Nevertheless, international guidelines assert that FH management should ideally be performed in a primary care setting.