A scoping review protocol to map the evidence on the risks and benefits of population based diabetic foot screening

Introduction

Diabetic foot ulcers are one of the most common lower extremity complications of diabetes, with the lifetime risk of a person with diabetes developing a DFU estimated to be as high as 34%¹. Diabetic foot ulcers increase the risk of lower extremity amputation and place a significant burden on the individual and the health system^2–5. They also lead to an increased risk of death, which increases further when a person undergoes an amputation^1,6,7. The average 5-year mortality is 30.5% after a DFU, 46.2% after a minor amputation and 56.6% after a major amputation⁸. In addition to the increased risk of death, DFUs are a leading cause of the global burden of disability, accounting for 2.1% of global years lived with a disability^9,10. They also negatively impact an individual’s health related quality of life^11–13, lead to increased risk of depression^14,15 and increased financial stress¹⁶.

The presence of one or more risk factors (e.g. foot deformity, peripheral neuropathy, peripheral artery disease) places those with diabetes at an increased risk of developing ulcerations and progressing to amputation^17–20. However, these risk factors can be identified through regular assessments by appropriately trained healthcare professionals^17–20. The International Working Group by the Diabetic Foot (IWGDF), an international consortium of clinical and academic experts in diabetic foot disease, recommends that those who have no previously identified risk factors for ulceration should be reviewed annually for signs and symptoms of loss of protective sensation and peripheral arterial disease. The rationale being that, in general, patients who have no risk factors are at a very low risk of developing a DFU, whereas evidence suggests a loss of protective sensation and/or peripheral arterial disease is predictive of DFU development^21,22. They then recommend that those who have loss of protective sensation and/or peripheral arterial disease should be screened for presence of foot deformity, excess callus, pre-ulcerative lesions on the foot and for a history of foot ulceration or lower-extremity amputation²². Table 1 outlines the risk factors, their definitions and associated screening tests, as outlined by the IWGDF.

As this paper focuses on DFUs and associated risk factors for onset, it is important to note that throughout the literature, the terms examination, assessment, screening and foot check are used to describe the annual review of the foot in diabetes to identify risk factors for ulceration^23–27. The term screening is defined as the “testing of people who either do not have or have not recognized the signs or symptoms of the condition being tested for” and “where the stated or implied purpose is to reduce risk for that individual of future ill health in relation to the condition being tested for, or to give information about risk that is deemed valuable for that individual even though risk cannot be altered”²⁸. In addition, screening tests are not diagnostic, but are used to identify a subset of the population who are at higher risk of a health problem or a condition, who should be referred for additional testing/assessment to determine whether the disease is present. In contrast, definitions around assessment and examination describe the process of investigating or inspecting to make a definitive diagnosis^29,30. The term diabetic foot screening will be used within this protocol to describe the annual review of the foot in diabetes.

In the case of diabetic foot ulcers, screening is the process of identifying risk factors for ulceration so those with risk factors can be referred for further assessment or diagnosis, and if necessary, receive appropriate management or treatment for the risk factor identified by skilled healthcare professionals trained in comprehensive assessment of the lower limb. For example, following further assessment those with peripheral arterial disease may need referral to vascular specialists to restore blood flow to the affected arteries³². The IWGDF also makes recommendations on screening frequency depending on risk factors identified. As outlined in Table 2, the IWGDF recommends that those who have no loss of protective sensation or peripheral arterial disease are stratified as risk level 0 and should be screened annually, whereas those identified as having risk factors are stratified within a higher risk level and should be assessed more frequently and ideally by a foot health specialist (e.g., a podiatrist)²².

The IWGDF also recommends that annual foot screenings be carried out as part of the patient’s regular diabetes care. Implementation of the IWGDF recommendations into clinical guidelines differs depending on the geographical location^22,26,33,34. Some international guidelines recommend that an annual diabetic foot screening be carried out by the person’s primary doctor or nurse whereas others recommended it be carried out by a healthcare professional with no specific advice on when, where or by whom^26,34,35. However, the diabetic foot care programmes that are present are not situated within a quality assured structured population health screening programme^23–25,36. Quality assurance processes are necessary to minimise error and improve performance using explicit standards²⁸. In the case of diabetic foot screening, this lack of quality assurance may be contributing factor to why many patients do not receive an annual diabetic foot screening or are only being referred for specialist diabetic foot care when they present with a “foot concern”^37–39. It is also important to note that although diabetic foot screening is recommended as part of a pathway of care, and in some countries as part of structured diabetes care, it can be costly and complex to organise, particularly given the increasing prevalence of diabetes and the limited time allotted for primary care visits²².

A potential alternative to current approaches would be to move diabetic foot screening into a structured quality-assured population health screening programme^40,41. However, there are principles to consider when deciding whether to implement a screening programme for a given disease or health problem^42,43. These principles (See Table 3) were first outlined by Wilson and Jungner (1968) for the WHO and they set the gold standard for determining the appropriateness of screening for a disease⁴³.

Over the years, these principles have informed decisions internationally on population health screening guidelines^42,44,45. A recent systematic review and Delphi consensus process identified, synthesised and consolidated all principles of screening published since Wilson and Jungner’s⁴². While the review assessed that many aspects of Wilson and Jungner’s criteria are still relevant today, it identified a shift towards principles that focus on operational or implementation issues of whole screening programmes, rather than just screening for the disease or condition in question. These operational or implementation issues including screening programme acceptability and ethics, benefits and harm, and quality and performance management are not addressed by Wilson and Jungner⁴². This scoping review will evaluate the evidence on population screening for the at-risk foot in diabetes using both the Wilson and Jungner, and the more recent Dowbrow and colleagues, principles of screening to ensure operational and implementation issues relating to diabetic foot are captured within the scoping review.

Methods

A scoping review is defined as “a form of knowledge synthesis that addresses an exploratory research question aimed at mapping key concepts, types of evidence, and gaps in research related to a defined area or field by systematically searching, selecting, and synthesizing existing knowledge”⁴⁶. The scoping review outlined within this protocol will be conducted in line with the framework by Arksey and O’Malley (2005) and the Joanna Briggs Institute (JBI) scoping review methodology^47,48. In line with recommendations by Arksey and O’Malley (2005), the authors recognise that the scoping review process may not be linear, and the researchers may need to engage with each stage in a reflexive way and potentially repeat steps to ensure the literature is covered comprehensively⁴⁸. Where changes need to be made, these will be outlined in the final scoping review report, which will be reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) extension for Scoping Reviews (PRISMA-ScR)⁴⁹.

Discussion

International guidelines recommend that all patients with diabetes should be assessed at least annually for the presence of the at-risk foot so interventions can be put in place to prevent progression to ulceration and amputation. While some countries have a form of diabetic foot screening, the screening is not part of a structured population health screening programme^23–25,36. One potential way of improving diabetic foot care and ensuring all patients with diabetes are offered an annual diabetic foot screening is by introducing it into a structured population health screening programme. However, little work has been carried out to examine the evidence on whether introduction of diabetic foot disease into a population health screening programme is an appropriate course of action to prevent diabetic foot related complications^42,43. This review will evaluate and map the evidence surrounding diabetic foot ulcers using the principles outlined by Wilson and Jungner. Findings generated have the potential to evaluate whether introduction of diabetic foot screening into a population health screening programme is appropriate and whether certain areas warrant further research.

Data availability

No data are associated with this article.