Experience and attitudes toward blended tube feeding in Dutch pediatric healthcare professionals: A cross‐sectional survey

Abstract

Background

Blended tube feeding (BTF)—enteral nutrition based on whole foods—is increasingly adopted as an alternative to commercial formulas in children requiring long‐term tube feeding. While parents often initiate this practice, healthcare professionals are crucial for its safe and effective implementation. This study explored the perspectives of Dutch pediatric healthcare professionals regarding BTF to identify knowledge gaps and support future clinical guidance.

Methods

We performed a cross‐sectional survey in 252 participants based in the Netherlands from February to May 2025. The self‐developed 30‐item questionnaire addressed BTF knowledge, attitudes, and experiences. Responses were analyzed descriptively.

Results

A total of 252 respondents completed the survey, primarily pediatric dietitians (n = 89) and pediatricians (n = 64). Familiarity with BTF was high (82%), and 56% had cared for children receiving it, most commonly via gastrostomy, although practices varied. Attitudes were generally positive (65%), particularly among dietitians (81%). Reported benefits included improved feeding tolerance (79%), reduced reflux/vomiting (72%), and improved stool patterns (67%); while caregiver burden (61%) and perceived parental insecurity regarding nutrition (28%) were the main challenges. Awareness of the 2022 national BTF position paper was low (54%), especially among physicians (20%), although 77% of healthcare professionals expressed interest in further education.

Conclusion

This nationwide survey reveals high familiarity and positive attitudes toward BTF among pediatric healthcare professionals but considerable variation in practice and limited awareness of existing guidelines. Future interventional studies, evidence‐based recommendations and professional training are needed to support consistent, family‐centered implementation.

INTRODUCTION

Enteral tube feeding (TF) delivers nutrition directly into the gastrointestinal tract and is indicated when oral intake is insufficient or unsafe, particularly in children with complex or chronic conditions requiring long‐term nutritional support. For children dependent on prolonged TF, gastrostomy placement can offer stable and practical access for home TF. ¹ Long‐term TF places a considerable clinical and practical burden on children and their families. In the Netherlands, the prevalence of pediatric home TF was reported at 83–92 per 100,000 children annually between 2010 and 2014; more recent national estimates are currently unavailable. ² Insights from the Dutch setting may be informative for other high‐income healthcare systems with established home enteral nutrition programs. Commercially prepared enteral formulas have been the standard of care since the 1970s, offering predictable nutrient composition and reliable growth outcomes. ³ , ⁴ , ⁵ Nevertheless, gastrointestinal symptoms such as gastroesophageal reflux, vomiting, diarrhea, and constipation remain common among children receiving long‐term TF. ¹ , ² In recent years, interest in alternative feeding approaches has grown, driven by both efforts to reduce feeding intolerance and by families seeking more natural and socially inclusive feeding practices. ⁶ , ⁷ , ⁸ Blended tube feeding (BTF), also referred to as blended diet, is an example of such an alternative approach. It involves the administration of pureed whole foods via the feeding tube, prepared either at home or commercially. Despite its increasing use, systematic data on healthcare professionals’ knowledge, attitudes, and practices regarding BTF are lacking, leaving unclear how it is adopted in routine pediatric care.

Current evidence on BTF is largely derived from observational studies and parent‐reported outcomes, with limited data available from interventional research. ⁹ , ¹⁰ , ¹¹ These studies suggest potential benefits of BTF, including improved feeding tolerance, increased dietary variety, and psychosocial gains such as enhanced participation in family meals and perceived quality of life. ¹² , ¹³ , ¹⁴ , ¹⁵ However, healthcare professionals often express caution, reflecting uncertainties related to patient selection, nutritional adequacy, infection risk, and tube occlusion. ¹⁶ , ¹⁷ Additional practical barriers, including preparation time, resource demands, and limited institutional support, further complicate implementation. ¹⁷ , ¹⁸ Previous studies indicate that healthcare professional confidence, training, and preparedness for BTF remain limited, frequently attributed to inconsistent institutional policies and a lack of formal guidance. ¹⁸ , ¹⁹ , ²⁰ , ²¹ Recently, several national and international position papers have aimed to address these gaps, including guidance from the Dutch Pediatric Dietitians Network (NKD) and Dutch Society of Pediatricians (NVK) in 2022, ²² and from the American Society of Parenteral and Enteral Nutrition (ASPEN) and European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) in 2023. ²³ , ²⁴ While these documents provide important frameworks for safe practice, their impact on real‐world clinical adoption and consistency of care remains unclear.

Therefore, this nationwide cross‐sectional survey aims to assess Dutch pediatric healthcare professionals’ perspectives and current practices related to BTF. While previous work has primarily focused on either professionals or parents, providing only a partial view, our study links professional insights with findings from a companion survey on parental experiences. This integration provides new information on the real‐world adoption of BTF and offers a comprehensive perspective to inform future evidence‐based, family‐centered implementation in pediatric nutrition care.

METHODS

Study design and participants

This cross‐sectional survey study was conducted in the Netherlands using an online questionnaire targeting healthcare professionals in pediatric gastroenterology and nutrition. The primary target group consisted of pediatricians and dietitians; however, other healthcare professionals involved in pediatric TF care, including nurses, nurse practitioners, physician assistants, and speech‐language pathologists, were also eligible to participate. Participation was voluntary and no restrictions were applied regarding type of healthcare setting (e.g., academic or nonacademic hospital, or private practice). Questionnaires with <97% completion were excluded from the analysis and study size was determined by the number of eligible healthcare professionals who completed the survey during the study period.

Survey development

A custom questionnaire was developed to assess knowledge, attitudes, and clinical experience with BTF in pediatric care (Supporting File 1). Due to a lack of validated instruments, this survey was designed by pediatricians and researchers with expertise in pediatric gastroenterology and clinical nutrition (N = 4). Content was informed by relevant literature to reflect current evidence and practice. Face and content validity were assessed through expert review by pediatric gastroenterologists (N = 3) and senior dietitians from the Dutch Pediatric Dietitians Network (Netwerk Kinderdiëtisten, NKD; N = 3), who evaluated the draft survey for clarity, feasibility, and clinical relevance. Their feedback was incorporated into the final version. The final survey contained 30 items across three thematic domains: general TF practices, knowledge and experience with BTF, and access to BTF‐related resources and research. The questionnaire included multiple‐choice and optional open‐text fields, with skip logic used to ensure that respondents were only presented with questions relevant to their professional role and experience.

Definitions

Commercial BTF was defined as commercially produced enteral formulas supplemented with a variable proportion of industrially added real foods. Home‐made BTF refers to any whole‐food blends prepared at home or in a commercial kitchen.

Recruitment

Recruitment was conducted between February to May 2025 through professional networks, including the Dutch Pediatric Dietitians Network (Netwerk Kinderdiëtisten, NKD), the pediatric section of the Dutch Society of Pediatrics (Nederlandse Vereniging voor Kindergeneeskunde, NVK), and several pediatric departments. Despite efforts to reach a broad target population, participation was voluntary and potential selection bias cannot be excluded. Informed consent was obtained digitally by proceeding to the questionnaire after reading the study information.

Data collection

Responses were collected using Castor EDC (version v2025.2.02, Amsterdam, the Netherlands). No directly identifying data were collected unless participants voluntarily provided their email address for potential follow‐up, making the dataset pseudonymous. All data were handled confidentially and stored securely in accordance with applicable data protection regulations.

Statistical analysis

Data were exported to Microsoft Excel (version 2408) and analyzed using IBM SPSS Statistics (version 28.0.1.1 (15)). In line with the exploratory design of the study, analyses were primarily descriptive. All categorical variables were summarized as frequencies and percentages. Associations between variables were explored using cross‐tabulations; the Chi‐square test was applied when expected cell counts were sufficient, and Fisher's exact test was used when assumptions for Chi‐square test were not met. The McNemar test was used to evaluate differences in paired categorical responses. There were no missing data for the variables included in the analysis. A two‐sided P‐value of <0.05 was considered statistically significant. Although several items addressed related topics, they were not designed to form composite scales; therefore, formal reliability testing was not applicable. No multivariable modeling, sampling adjustments, or sensitivity analyses were applied.

Ethical considerations

Our survey study was assessed by the Ethics Committees of Amsterdam UMC (Protocol 2025.0066), adhering to the Declaration of Helsinki principles. The research was determined by the Ethics Committees of Amsterdam UMC to be exempt from full review due to minimal risk to surveyed participants. Participation was voluntary, and caregivers could discontinue the survey at any time without providing a reason.

RESULTS

Participant characteristics

A total of 294 healthcare professionals accessed the survey. After excluding 42 incomplete questionnaires, 252 questionnaires were included in the analysis, corresponding to an overall completion rate of 86%. Main respondents were pediatric dietitians (n = 89, 35%), pediatricians (n = 64; 25%), dietitians (n = 45; 18%), and pediatric gastroenterologists (n = 18; 7.1%). Respondents represented 48 different hospitals, in addition to private practices and other healthcare facilities. All professions and practice settings are listed in Table 1.

Table 1.

Participant characteristics.

	Number (N)	Percentage (%)
Profession (N = 252)1 , 2
Pediatric dietitian	89	35.3
Dietitian	45	17.9
Dietitian intellectual disability medicine	14	5.6
Pediatrician	64	25.4
Pediatric gastroenterologist	18	7.1
Pediatric resident	8	3.2
General physician or practitioner	10	4.0
Nurse practitioner/physician assistant	10	4.0
Other3	38	15.1
Practice setting (N = 252)1 , 4
General hospital	114	45.2
Academic (university) hospital	67	26.6
Private or group practice	41	16.3
Outpatient clinic or healthcare facility	22	8.7
Other5	22	8.7

¹ Multiple responses were permitted for this item; as a result, the cumulative percentage may exceed 100%.

² In total, 296 responses were recorded for this item (mean 1.2 responses per respondent).

³ Other professions included pediatric specialists (e.g., congenital disorders, social pediatrics, youth healthcare, child and youth psychiatry, surgery, intellectual disability and rehabilitation medicine), (pediatric) nurses, speech–language pathologists, and urological therapists.

⁴ In total, 266 responses were recorded for this item (mean 1.1 responses per respondent).

⁵ Other care settings included private or group practice, outpatient clinic or healthcare facilities (e.g., psychiatric institutions, rehabilitation centers), and home care.

Reported TF practices

Of all respondents, 213 (85%) reported providing care for children receiving TF. Among these respondents, 53% were dietitians and 47% physicians. Pediatric dietitians were most frequently identified as the primary professionals managing TF care (n = 186, 74%), followed by pediatricians (n = 107, 43%).

Most respondents reported providing TF care for 10–50 children annually (n = 100, 47%), followed by <10 (n = 75, 35%) or >50 children (n = 36, 17%). Among those treating >50 children annually, dietitians were more frequently represented than physicians (77% vs 23%) and were more often based in academic hospitals than in general hospitals (74% vs 26%).

Main indications for initiating TF are summarized in Table S1.

Reported knowledge and awareness of BTF

Among all respondents, the majority reported being familiar with BTF (n = 206, 82%). Familiarity was more common among dietitians than physicians (97% vs 75%) and differed modestly across practice settings (77%–84%), with the highest proportion reported in academic hospitals. Sources of awareness are presented in Table S2.

Reported BTF practices

All reported BTF practices are summarized in Table 2. Among respondents providing TF care (N = 213), 142 (56%) reported experience with BTF. BTF provision was more frequently reported by dietitians than physicians (79% vs 42%) and was most common in academic hospitals.

Table 2.

Reported blended tube feeding practices.

	Number (N)	Percentage (%)
Participants managing children receiving BTF (N = 252)
Yes	142	56.3
Type of BTF (N = 142)1
Home‐made BTF	25	17.6
Commercial BTF	27	19.0
Both	90	63.4
No	110	43.7
Tube types for BTF administration (N = 206)1 , 2 , 3
Gastrostomy with or without Mic‐key button	127	61.6
Nasogastric tube	62	30.1
(Naso)duodenal tube	9	4.4
Jejunostomy catheter	8	3.9
Minimal tube size in Charrière (Ch) for home‐made BTF (N = 115)1
Ch 8	8	7.0
Ch 10	14	12.2
Ch 12	18	15.7
Ch 14	30	26.1
Ch ≥ 16	2	1.8
No minimum	2	1.7
Uncertain	34	29.5
Use of BTF: partial versus exclusive (N = 142) 1 , 2 , 4
Exclusively BTF	93	65.5
Partially BTF with commercial TF	93	65.5
Partially BTF with oral intake	91	64.1
Partially BTF with additional supplements	75	52.8
Growth parameter monitoring (N = 142)1
Never	1	0.7
Every month	22	15.5
Every 3 months	52	36.6
Every 6 months	7	4.9
Every year or less	2	1.4
Other5	58	40.8
Laboratory parameter monitoring (N = 142) 1 , 6
Not routinely monitored	61	43.0
Hematology	24	16.9
Iron	19	13.4
Electrolytes	16	11.3
Vitamins	15	10.6
Other7	62	43.7

Abbreviations: BTF, blended tube feeding; TF, tube feeding.

¹ Due to the use of skip logic, this question was presented only to respondents who provided a specific response to the preceding question.

² Multiple responses were permitted for this item; as a result, the cumulative percentage may exceed 100%.

³ In total, 206 responses were recorded for this item (mean 1.0 responses per respondent).

⁴ In total, 352 responses were recorded for this item (mean 2.5 responses per respondent).

⁵ Other growth‐monitoring practices included adjusting the frequency based on clinical factors, including the child's age, underlying condition, weight status, duration of tube feeding, treatment goals, and coordination with pediatrician visits.

⁶ In total, 197 responses were recorded for this item (mean 1.4 responses per respondent).

⁷ Other laboratory monitoring practices included adapting frequency to the individual case, BTF type (commercial vs home‐made), underlying disorder, and indications such as poor growth, feeding intolerance, suspected deficiencies, or symptoms.

Most respondents providing BTF reported using both commercial and home‐made BTF (n = 90, 63%). Gastrostomy tubes (n = 105, 51%) were used most frequently, followed by nasogastric tubes (n = 62, 30%). Uncertainty regarding the minimum tube size for home‐made BTF was reported by many respondents (n = 34, 30%), particularly among dietitians (33% vs. 17% physicians).

Reported monitoring practices for growth parameters and laboratory outcomes showed substantial variation. No statistically significant differences were observed between professions or practice settings.

Reported attitudes toward BTF

Among respondents familiar with BTF (N = 206), most reported recommending BTF (n = 133, 65%). Recommendation rates differed significantly different between dietitians and physicians (81% vs 50%, P < 0.001), while no differences were observed across practice settings. The most frequently reported reasons for recommending BTF were perceived improved feeding tolerance (n = 117, 80%), positive results in other patients (n = 94, 64%), and perceived positive effect on the microbiome (n = 89, 61%). Reasons against recommending BTF are summarized in Table S3.

Reported experience with BTF

Among respondents with experience in commercial BTF, 85 (41%) rated their experiences positively. Higher proportions were reported by dietitians compared with physicians (57% vs 24%, P < 0.001), and by respondents working in academic hospitals or private practice compared with general hospitals. For home‐made BTF, 109 respondents (53%) reported a positive experience, again more frequently among dietitians than physicians (60% vs 44%) and among respondents working in academic hospitals. Reported experience with BTF is shown in Figure 1.

Figure 1.

Reported experience with commercial and home‐made blended tube feeding (BTF) among healthcare professionals. Bars represent the percentage of respondents reporting positive, neutral, negative, or uncertain experiences.

The most frequently reported positive clinical experiences included improved feeding tolerance (n = 112, 79%), reduced gastroesophageal reflux and/or vomiting (n = 102, 72%), and improved bowel movements or stool consistency (n = 95, 67%). The most frequently reported negative clinical experiences were increased caregiver burden (n = 87, 61%), perceived parental concern or insecurity regarding nutritional adequacy (n = 39, 28%), and feeding tube occlusions (n = 29, 20%).

Paired McNemar analyses showed that participants reported significantly more positive than negative clinical experiences for most outcomes (P < 0.001). In contrast, negative experiences were reported more frequently for tube occlusions (P < 0.001), while no significant differences were observed for growth or infection rates (see Table S4).

Reported access to information and education on BTF

Among respondents familiar with BTF (N = 206), 54% reported familiarity with the national BTF position paper with marked differences between dietitians (84%) and physicians (20%).

Availability of educational materials was limited (Table S5). Many respondents (77%) expressed interest in additional training and guidance on BTF, with similar proportions reported by dietitians and physicians.

Key priorities for future clinical care and research are summarized in Table S5. Growth and development was the most frequently reported priority for both domains, followed by quality of life and psychosocial outcomes. No differences were observed between professions or practice settings.

DISCUSSION

BTF is becoming an increasingly important option in pediatric feeding care, yet its adoption remains inconsistent across clinical settings. This study, paired with a companion survey among parents, ²⁵ reveals that, while BTF is increasingly recognized, its implementation differs due to varying levels of professional exposure, information, and institutional support. These findings underscore the critical need for clear, evidence‐based guidelines, improved training for healthcare professionals, and communication between healthcare professionals and families to ensure more consistent and effective BTF use in pediatric care.

In this study, familiarity with BTF was widespread (82%), particularly among dietitians (97%), exceeding the 28%–66% reported in previous international studies. ¹⁹ , ²¹ , ²⁶ However, hands‐on experience was not evenly distributed. Dietitians reported significantly higher awareness and practical experience than physicians, likely reflecting differences in training, professional responsibilities, and clinical settings. This aligns with findings from international studies where dietitians, central to enteral nutrition management, tend to have more exposure to BTF cases. ²¹ Additionally, healthcare professionals working in academic centers reported considerably more experience, suggesting that institutional culture and available resources further shape the frequency of BTF application in clinical practice. The differences in exposure and training were reflected in the variability of practices reported by healthcare professionals. Approaches to feeding routes, tube sizes, and monitoring strategies varied widely, with many healthcare professionals (30%) expressing uncertainty about best practices. Notably, nasogastric tubes, including tube sizes below 10 Charrière (Ch), were reported despite being generally discouraged in BTF guidance because of the increased risk of tube occlusions associated with more viscous feeds. ²³ , ²⁴ The reported use of jejunostomies was equally notable, as jejunal feeding is considered a relative contraindication in both national and international guidance. ²² , ²³ , ²⁴ These findings illustrate the variation in clinical practice and underscore the need for well‐defined, evidence‐based guidelines on BTF. A similar lack of standardization was observed in monitoring practices. Although growth monitoring and laboratory assessments were commonly reported, considerable variation existed in the type and frequency of follow‐up. While international recommendations provide practical guidance for the monitoring of children receiving BTF, ²³ , ²⁴ the evidence underpinning these recommendations remains limited. The wide variation in monitoring practices observed may therefore reflect ongoing uncertainty regarding optimal follow‐up strategies and highlights an important area for future research and guideline development. In our study, high familiarity with the national BTF position paper did not seem to translate into consistent clinical practices, possibly due to its more advisory nature compared to the more operational guidance found in frameworks such as those from ASPEN and ESPGHAN. ²³ , ²⁴ Dietitians were significantly more familiar with the Dutch position paper (84% vs 20% physicians) and expressed more favorable attitudes toward BTF, including a higher likelihood of recommending its use. This observed association between guideline familiarity and professional confidence is consistent with previous reports highlighting that limited access to practical guidance is accompanied by uncertainty and reluctance among healthcare professionals to support BTF. ¹⁶

Current guidance on BTF is built on over a decade of research showing both promising effects and challenges in implementing BTF in pediatric care. ¹¹ , ²⁷ , ²⁸ In our study, healthcare professionals who reported using BTF frequently perceived clinical benefits. The majority observed improvements in feeding tolerance (79%), with several also noting increased oral intake (29%), and improved quality of life (24%) among children receiving BTF. These reported clinical experiences closely mirror findings from earlier observational studies, ⁴ , ²⁹ , ³⁰ , ³¹ , ³² and align with the perceived benefits reported by parents in the companion survey, ²⁵ together reinforcing the overall picture of good tolerability and broad perceived benefit. Taken together, these findings suggest that BTF may reduce symptoms, with potential downstream effects on medication use, reliance on medical interventions, hospital visits, and overall healthcare utilization, supporting its consideration as a potentially sustainable and cost‐effective option in pediatric nutrition care. ¹² , ³³ However, our findings must be interpreted with caution, as both the parent and healthcare professional datasets reflect perceived rather than objective clinical outcomes. This distinction is particularly relevant for TF occlusions. Approximately 20% of healthcare professionals perceived tube occlusion as a challenge associated with BTF, reflecting professional concerns regarding tube blockage rather than its actual occurrence.

Despite the convergence in perceived benefits, a divergence emerged regarding the barriers to BTF initiation. Both healthcare professionals and parents frequently reported increased caregiver burden as a significant obstacle (61% and 44%, respectively). However, while healthcare professionals emphasized concerns regarding caregiver capacity (such as difficulties in instructing families and anticipated resource intensity), parents often reported insufficient knowledge and guidance from their healthcare professionals, as also demonstrated in the companion survey. ²⁵ When directly comparing reported barriers, healthcare professionals appeared to overestimate caregiver burden and parental concern or insecurity related to feeding (perceived parental concern: 28% of healthcare professionals vs 15% of parents). Together, these differences reflect a two‐way confidence gap between families and healthcare professionals, which may constrain shared decision making. Bridging this gap will require clearer communication, enhanced professional coaching, and more aligned expectations on both sides, thereby supporting more collaborative and effective BTF adoption.

Our study also highlights significant system‐level challenges to integration of BTF. Many healthcare professionals reported limited access to educational materials, training, and institutional protocols, with a third of respondents indicating they had never received information or training on BTF. These gaps are consistent with international studies that emphasize the lack of formal training and institutional support for BTF. ¹⁶ , ¹⁸ , ¹⁹ , ²¹ , ²⁶ These limitations are concerning because they likely reduce healthcare professionals’ confidence in recommending or implementing BTF, and may lead to inconsistent care, increased risk of complications, and less effective patient outcomes. Many respondents (77%) expressed strong interest in receiving more structured education and clearer, evidence‐informed guidance. These findings underscore the critical role of institutional readiness in facilitating BTF adoption. National guidelines, when paired with operational frameworks, could provide the necessary support to ensure consistent, informed care. The lack of comprehensive training and resources also points to the need for ongoing research to inform such guidelines. Much of the existing BTF evidence remains retrospective and small scale, which underscores the importance of conducting prospective and interventional studies to assess both clinical outcomes and the experiences of families. Through the companion parent survey, ²⁵ we gained a unique two‐sided perspective on what healthcare professionals and parents consider essential for future care and research. Both groups identified growth, development, and quality of life as priority outcomes for future research. These findings highlight the need to consider both clinical and psychosocial aspects of BTF care in future guidelines, as the effectiveness of BTF is determined not only by medical outcomes but also by its impact on the well‐being of families. To move the field forward, future research must go beyond descriptive surveys and focus on evaluating how BTF can be safely and effectively incorporated across diverse clinical settings. ³⁴

This study's strengths include its nationwide scope and multidisciplinary sample. To our knowledge, this is the first study integrating both professional and parental perspectives through a companion survey. ²⁵ These features provide a comprehensive view of BTF implementation across pediatric care settings. However, there are limitations. The survey was self‐developed and self‐reported, which may introduce recall bias and potential limitations in the validity of the data. Additionally, because the survey was conducted via an open‐link design, a response rate could not be formally calculated, potentially introducing nonresponse bias. The study's cross‐sectional design prevents conclusions about causal relationships between the variables, and objective clinical outcomes were not measured, limiting the ability to assess the direct impact of BTF on patient health.

CONCLUSION & FUTURE RECOMMENDATIONS

In this study, paired with a companion survey among parents, ²⁵ we identified significant variability in the adoption of BTF across pediatric care settings, particularly in professional readiness and institutional support. While healthcare professionals report promising benefits, its implementation is hindered by gaps in training, evidence‐based guidelines, and institutional resources. To ensure more consistent BTF adoption, healthcare institutions must prioritize well‐structured training programs for all healthcare professionals. Improved communication and shared decision making between healthcare professionals and families are essential to support mutual confidence in BTF use. Future research should focus on interventional studies to assess the long‐term clinical outcomes and cost‐effectiveness of BTF, while also considering the psychosocial impact on the child and their families, as these are crucial for developing comprehensive, sustainable, and family‐centered guidance.

AUTHOR CONTRIBUTIONS

R. S. Boereboom: Conceptualization; investigation; funding acquisition; writing—original draft; methodology; validation; visualization; writing—review and editing; software; formal analysis; project administration; data curation; resources. E. H. Jongh‐Kampherbeek: Writing—review and editing; validation; conceptualization. M. Groenewold: Conceptualization; validation; writing—review and editing. C. G. W. Ophuizen: Conceptualization; validation; writing—review and editing. T. G. J. Meij: Conceptualization; validation; visualization; writing—review and editing; supervision; resources; project administration. J. B. Goudoever: Conceptualization; validation; visualization; writing—review and editing; supervision; resources; project administration. A. Kindermann: Conceptualization; investigation; funding acquisition; methodology; validation; visualization; writing—review and editing; project administration; supervision; resources.

CONFLICT OF INTEREST STATEMENT

None declared.

Supporting information

Additional supporting information may be found online in the Supporting Information section at the end of the article.

Supporting File 1.

Supporting File 2.