FormalPara Key Summary Points

The International Working Group on the Diabetic Foot (IWGDF) has been producing evidence-based guidelines on the management and prevention of diabetes-related foot disease for almost three decades.

The 2023 IWGDF update has just been published, consisting of practical guidelines, 7 guidelines, 11 systematic reviews, 1 methodology and 1 definitions and criteria document.

We estimate that the 2023 update of the IWGDF Guidelines required a total 10 years of full-time work, which would have cost 2 million euros if the voluntary work had been financially compensated.

Currently available translations of the IWGDF Guidelines serve 2.9 billion people globally in their native language.

Introduction

Foot disease is a devastating complication of diabetes. Awareness of the complexity of the treatment of this disease started to increase in the 1980s, when the King’s College Hospital multidisciplinary foot clinic became the global example [1], when the first (and still running) conference dedicated to the topic was organised in Malvern, UK, and when the 1989 St. Vincent declaration called to reduce diabetes-related amputations by 50% [2]. In the 1990s, increased awareness continued. The first international conference was organized in 1991 in Noordwijkerhout, The Netherlands, and the number of yearly papers on PubMed more than doubled (the free-text search “diabetic foot” gives a mean 68 publications annually in the 1980s versus 203 in the 1990s), and multidisciplinary clinics were founded globally. All of this led to the creation of the International Working Group on the Diabetic Foot (IWGDF), an independent multidisciplinary group of clinicians and researchers dedicated to diabetes-related foot disease. The IWGDF set out to produce an “international set of definitions and guidelines on prevention and management of diabetes-related foot disease”, resulting in the “International Consensus and Practical Guidelines” presented at the International Symposium on the Diabetic Foot in 1999 [3]. Since then, these IWGDF Guidelines have been updated every 4 years. The aim of this article is to give the reader a better understanding of the IWGDF Guidelines, as this unique global collaboration of volunteering professionals is now approaching 3 decades of working towards reducing the high patient and societal burden of diabetes-related foot disease. Specifically, we aim to describe the history of these guidelines, outline the most recent guidelines (the 2023 update), describe the changes over the years and their rationale, quantify efforts required to produce these guidelines, and describe translation and implementation processes. We hope the reader will consequently be better informed about ‘the story behind’ the IWGDF Guidelines, thus facilitating improved uptake of the recommendations described in the guidelines.

Diabetes-Related Foot Disease

Diabetes-related foot disease is defined as a “disease of the foot of a person with current or previously diagnosed diabetes mellitus that includes one or more of the following: peripheral neuropathy, peripheral artery disease, infection, ulcer(s), neuro-osteoarthropathy, gangrene, or amputation” [4]. It is a common, complex, and costly complication of diabetes: common because 199 million people are affected with diabetes-related foot disease according to estimates of the Global Burden of Disease study [5]; complex because the treatment requires coordinated treatment efforts from multiple healthcare professionals within different fields of knowledge (see Table 2 in [6]), and treatment may take several months to over a year taking a great toll on the people’s life expectancy and quality of life; costly because when ranking the burden for individuals with diseases, diabetes-related foot disease ranks as the 11th largest condition of global disability burden. It ranks higher than, for example, dementia, ischaemic heart disease or breast cancer [7]; it is costly because of the treatment costs required, with one ulcer episode costing on average 10,000 euros [8].

Conditions for the successful management of such a common, complex and costly disease, especially with the multiple disciplines involved, include a shared knowledge base and language, a shared sense of urgency and aims, and a systematic multifactorial team approach. It was with these conditions for the management of diabetes-related foot disease in mind that the IWGDF was founded in 1996. Even now, the mission of the IWGDF is still to produce evidence-based guidelines to inform health care providers worldwide on strategies for the prevention and management of diabetes-related foot disease; thus, the IWGDF aims to reduce the high patient and societal burden of diabetes-related foot disease [9].

The IWGDF Guidelines

History of the IWGDF Guidelines

The first IWGDF Guidelines, presented in 1999 and published as both a book [10] and a summarizing journal paper [3], were written by a ‘full working party’ of 45 experts from 23 countries. Most of the work was undertaken by the Editorial Board, chaired by Karel Bakker, and further consisting of Nicolaas Schaper (scientific secretary), Jan Apelqvist, William van Houtum and Marrigje Nabuurs-Fransen. With no widely accepted methodology existing for guideline production, the Editorial Board and all the working group members combined thorough literature searching with expert opinion to provide draft guideline texts. These drafts were extensively discussed, and frequently rewritten, and in the end, consensus and sign-off from all 45 experts was achieved. The first-ever global guidelines on the topic were born.

A unique aspect of the IWGDF Guidelines then followed: successful updates every 4 years (Fig. 1). National guidelines are frequently left without an update for years or even decades (see, for example, The Netherlands—guidelines in 2006 and 2017 [11]; Australia—guidelines in 2011 and 2022 [12]; the UK—guidelines in 2004 and 2015, with very minor updates of specific sections in 2019 and 2023 [13]). By comparison, the IWGDF has completely updated their guidelines every 4 years since its inception, and all are freely available both on the IWGDF website and in journal publications. We have identified three key factors in the success of these continuous updates:

  • The dedication of the working group members, all with the focus of caring for and improving outcomes of diabetes-related foot disease, the disease sometimes referred to as the Cinderella complication [14];

  • The hard external deadline, being the quadrennial International Symposium on the Diabetic Foot (http://www.isdf.nl), as the podium where the guidelines are presented to the public;

  • The procedure, jokingly and amicably referred to as the Karel-Bakker method of “guideline by starvation”, especially in the early updates, where the working group was “forced” to remain in the meeting room until they completed their tasks!

Fig. 1
figure 1

The front page of all IWGDF Guidelines and their year of publication

Full size image

Having continuous updates is important for multiple reasons. First, it allows for incorporation of new evidence into recommendations for clinical practice. Second, we think that more recent guidelines in an ever-changing world come across as more reliable for healthcare professionals who are entering the field. Third, it allows for improvement in the methods used to write these guidelines, as can be seen in the changes in the IWGDF methodology over the years.

From Expert Opinion to Evidence Based

The first and second IWGDF Guidelines were documents that would now be considered “expert opinion documents”, even though the working group members assessed hundreds of peer-reviewed publications in the process of writing them, but not with a systematic approach. The first real changes in methodology appeared in the 2007 update. Three specific guidelines were added, each based on a systematic review of the literature. With each subsequent update, further improvements were introduced (Table 1). The largest improvement was the implementation of the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) evidence-to-decision framework [15, 16]. In 2019, we implemented a so-called “GRADE light”, while in the 2023 update the full GRADE approach was implemented [9, 17]. To support this implementation, all working group members involved in the 2023 update were trained through the International Guideline Development Credentialing & Certification Program (http://www.inguide.org) at the guideline panel member level (level 1) and at least two members of each working group at the guideline methodologist level (level 2). As a result, the IWGDF guidelines have grown from one expert opinion document to a set of seven evidence-based guidelines [18,19,20,21,22,23,24,25,26,27], summarized in the practical guidelines [6] and supported by 11 systematic reviews [28,29,30,31,32,33,34,35,36,37,38], a detailed methodology document [9] and a definitions and criteria consensus document [4] (Table 1).

Table 1 Overview of the IWGDF Guidelines and their supporting documents
Full size table

Hand in hand with the methodological changes, the topics covered in the IWGDF Guidelines were also extended with each update, from three specific guidelines on offloading, infection and wound bed management in 2007, via specific guidelines on peripheral artery disease (PAD) in 2011, on prevention of foot ulcers in 2015, on classification in 2019 and on Charcot’s neuro-osteo-arthropathy in 2023 (Table 1). Furthermore, the 2023 update also incorporated new collaborations: with the Infectious Disease Society America for the infection guideline [20, 21] and with the European Society for Vascular Surgery and the Society for Vascular Surgery for the PAD guideline [22,23,24]. This resulted in the first-ever global intersocietal guidelines on these topics, to extend the impact to a wider audience, and with these societies simultaneously publishing these guidelines on their own websites and journals as well. These methodological and content changes and additions reflect the efforts of the IWGDF to increase the quality and thoroughness of the IWGDF Guidelines to keep up with current day standards of guideline development.

Numbers Behind the IWGDF Guidelines

One of the potential reasons why guidelines are generally only seldom updated relies on the huge amount of work involved in producing evidence-based guidelines. The IWGDF counts themselves extremely lucky by having such a large base of dedicated working group members and external experts. Working group members were healthcare professionals and clinical scientists who were considered experts on the topic of the specific guideline. They were proposed by the chair of each working group, based on the track record from peer-reviewed scientific publications, contributions to conferences and involvement in (local) care improvements. Chairs were provided with input from both the IWGDF Editorial Board and from people outside IWGDF. In addition, professional background and country of residence were considered to create a balanced, multidisciplinary and international working group. People with a conflict of interest could not participate in a working group. The proposed working group, including all members, was then formally approved by the IWGDF Editorial Board. External experts were healthcare professionals involved in daily care of people with diabetes-related foot disease and were proposed by working group members, by D-Foot International and by other people from outside IWGDF. Care was taken to include external experts from countries who were not represented in a working group to facilitate future implementation. External experts could not participate in a working group to avoid potential conflicting interests and to share the workload. All working group members contributed their time voluntarily. No IWGDF working group member has ever received payment for any of their efforts. The unrestricted grants from companies have only been used to organise meetings and to pay for travel and accommodation of the working group members, and companies have not been involved in any way in the production of these guidelines. For further information on sponsorship and conflict of interest management, see the declaration section at the end of this article and the detailed descriptions of how conflict of interests was handled in each guideline [18,19,20,21,22,23,24,25,26,27].

To provide some insights into the work required to produce the IWGDF Guidelines, we have tried to summarise it in numbers (Fig. 2). We acknowledge that these are estimates, based only on our experiences, with no formal method or quantification followed. As a result, we may under- or overestimate the efforts involved. Despite these limitations, we still think this gives a useful representation of the work required (Fig. 2).

Fig. 2
figure 2

Numbers behind the IWGDF Guidelines (2023 update). We considered 1800 h equivalent of one full-time working year and €200,000 financial remuneration for 1 full-time year; Editorial Board calculations are based on 160 meeting hours and their preparation and writing and peer review of all 21 IWGDF documents; Working Group calculations are based on 75 meeting hours and their preparation per working group, and 50 review hours of the peer-reviewed literature, for each of the 69 working group members; Chair and Secretary calculations are based on 150 h of project management and 170 h of tables and manuscript writing; Peer review of external experts (estimated at 18 h per person for an average 2 guidelines per expert) is not taken into account in the figure

Full size image

Numbers to quantify the uptake of the IWGDF Guidelines are also hard to obtain. Books and hard copy papers may be shared; download numbers are not representative of actual use, and most of these metrics were not even tracked in the earlier versions. What can be seen on the website metrics is that the webpage with the IWGDF Guidelines 2019 update has been accessed by > 15,000 people from > 150 countries, suggesting huge global uptake. A metric that is reliably available concerns scientific citations. Even though the IWGDF guidelines are primarily meant to be used in clinical practice, their citations do underline the importance: the last five practical guidelines (2007–2023) have collectively been cited 789 times (Web of Science ISI; search date: 08-SEP-2023), a total five IWGDF documents [39,40,41,42,43] are in the top 1% of the field of Clinical Medicine regarding their citations (Web of science ISI; search date: 08-SEP-2023), and, of the top-10 most cited papers from Diabetes Metabolism Research and Reviews, five are IWGDF publications (https://onlinelibrary.wiley.com/page/journal/15207560/homepage/most-cited; date accessed: 08-SEP-2023).

Translation and Implementation

Having global evidence-based guidelines is just the start. Once the IWGDF Guidelines are completed and presented, it can be argued that the real work starts: implementing the recommendations in clinical practice. Over the years, various studies have shown that implementation of the IWGDF Guidelines improves outcomes [44, 45] or general improvements in multidisciplinary care for people with diabetes-related foot disease as recommended in the IWGDF Guidelines improves outcomes [46]. Modelling analyses further show that investing in implementing guidelines is likely cost-effective [47].

A unique feature is the global outreach of the IWGDF. Delegates from 63 countries, from all continents, were involved in the production of the 2023 guidelines to enable global applicability as much as possible. However, the IWGDF is too small an organisation to support local implementation and guideline uptake. Also, when formulating global guidelines, it is nearly impossible to consider all local factors that affect the applicability of the recommendations, such as culture, climate, organization of health care and availability of resources. Moreover, the text is written in English, which is a major barrier for many health care workers. IWGDF therefore supports translations and adaptations. Over the years, the IWGDF Guidelines have been translated in at least 26 languages (https://iwgdfguidelines.org/translations/). IWGDF transfers the copyright for their guidelines to diabetes or diabetes-related foot disease associations in each country. These associations then translate and publish the documents, accompanied by local implementation meetings. The 2019 update has been translated in 16 languages (Fig. 3). Including the translation in Farsi of the 2015 IWGDF update, and the almost completed translation in Bahasa-Indonesian, these languages collectively serve 2.9 billion people for whom one of these languages is their native language.

Fig. 3
figure 3

Translations of the IWGDF Guidelines (2019 update)

Full size image

Some countries go beyond translation, and into adaptation. IWGDF allows for the IWGDF Guidelines to be adapted to local views and situations, as the prevalence, spectrum, health services’ structure and treatment opportunities for diabetes-related foot disease vary around the world. When adapted, differences between the original IWGDF Guidelines and the new local guidelines must be clearly highlighted. Ideally, adaptation is also done using the GRADE approach for adoption [48], as Australia, Tunisia and the Czech Republic have done for the 2019 update (see https://iwgdfguidelines.org/translations/).

The translation process of the 2023 update has already started. Once again, we support associations to translate the guidelines in the major global languages (e.g. Mandarin, Spanish, French, Portuguese, Bahasa-Indonesian, German) as well as in languages with a smaller audience (e.g. Slovenian, Croatian, Hebrew). In addition to the enormous efforts of local translation committees, we are now also supported by the DeepL artificial intelligence tool. This speeds the process and leaves the local teams more time for implementation.

A translation is just the beginning of local implementation. IWGDF is not directly involved in local implementation projects. This is done by local teams and often supported by D-Foot International with their training and outreach programmes.

Discussion and Conclusion

Every 20 s, someone in the world has an amputation of (part of) the leg because of diabetes, and diabetes-related foot disease ranks 11th globally among diseases that pose the heaviest burden on patients and society [5]. For many years management of this “Cinderella” of diabetes-related complications was hampered by a lack of understanding of the underlying multifactorial pathology, lack of diagnostic and therapeutic tools and poor organization of care [14]. To treat diabetes-related foot disease effectively, a clinician needs to address pathological factors including peripheral artery disease, neuropathy, infection, altered biomechanics and mobility, impaired wound healing, metabolic control and the presence of other diabetes-related complications as well as the psychosocial and behavioural issues of self-care, access to care and many more. These topics are clearly not the domain of one specific medical discipline, but failing to address any of them will increase the risk of poor outcomes. Also, in our experience, many healthcare workers still hold beliefs that are not in line with the latest developments, and such misconceptions will further increase the risk of adverse outcomes [49, 50]. It is therefore essential that any healthcare worker involved has access to multidisciplinary guidelines based on input of all relevant disciplines and stakeholders to guide their management.

The IWGDF is an independent organization which is not linked to any specific medical discipline and produces multidisciplinary guidelines (> 10 different disciplines involved in the latest version). This contrasts with other guidelines on this topic, which frequently are produced under the umbrella of one medical organisation. The number of scientific publications on diabetes-related foot disease has markedly increased in recent decades, and although progress can be slow, what is seen as best standard of care in one specific area can change within a few years, another reason for our guidelines to be updated every 4 years. Another distinctive aspect is the involvement of the (North American) Society for Vascular Surgery, the European Society for Vascular Surgery and the Infectious Diseases Society of America in our 2023 version. This resulted in two intersocietal guidelines that are also integrated into the other chapters of IWGDF guidelines [20,21,22,23,24].

This independence, and the guideline-writing by multidisciplinary working groups of dedicated and well-trained clinicians and clinical researchers who all work at the coalface of the disease, are key strengths of IWGDF. However, as also depicted in Fig. 2, the workload associated with this is a threat. All contributions are made voluntarily, and IWGDF is dependent on their working group members, especially the chairs and secretaries. With 30 years of history behind us, we hope that these members will continue to pursue our mission to reduce the high patient and society burden of diabetes-related foot disease with high-quality guidelines.

Future developments that are currently not completely clear to us and the wider medical community concern the position of ‘static’ guidelines. We do not know if the current guidelines, updated every 4 years, will still apply given the changes in health care systems and health care personnel globally. However, these changes also offer opportunities. As IWGDF, we have already showed with our 2023 update that we could adapt and move from guideline writing via one extensive face-to-face meeting to many online meetings. We are positive that we will continue to adapt to changing systems to produce meaningful and usable clinical guidelines.

In addition to clinical guidelines, IWGDF has also been shown to lead the scientific discussion. The systematic reviews underlying the IWGDF Guidelines have continuously shown the weaknesses in existing evidence, especially from a trial design perspective. Subsequently, we have defined in collaboration with the European Wound Management Association, the standards of reporting and required details when publishing results of intervention trials in diabetes-related foot disease [51]. These are now increasingly used in RCTs, improving the quality of the evidence in our field. However, more work needs to be done to improve the quality of clinical research. The dedicated ‘future research’ sections in each guideline also drive the research agenda. These originate from the evaluation of all the available evidence by each working group, allowing the identification of our present knowledge and future research prioritizations. Third, we developed a set of definitions and criteria to ensure effective communication [4, 42]. The high uptake in research papers, as shown by > 150 citations within 4 years, shows that the field is actively using this document. Together, this results in high-quality evidence on the topics that are most important for daily clinical practice.

In conclusion, after almost 3 decades of producing evidence-based clinical guidelines on the prevention and management of diabetes-related foot disease, IWGDF hopes that the 2023 update will continue to stimulate clinicians to deliver the best care possible for these patients, will motivate researchers to undertake the high-quality trials needed to deliver the new evidence to advance the field further and collectively will support people with diabetes-related foot disease to minimize their disease burdens.