A Protocol for a Scoping Review to assess the influence of psychological factors on the development and progression of diabetes-related foot ulcers

Rationale for this research

Early intervention for DFU is listed as a key priority in both national and international guidelines and strategies (HSE: Model of Care for the Diabetic Foot, 2021; International Working Group of the Diabetic Foot (IWGDF, 2023); NHS: National Diabetes Foot Care Audit, 2022. However, despite this international consensus on care delivery based on risk, a systematic review of prevention strategies concluded that the evidence base for interventions to prevent first foot ulcers is ‘practically non-existent’ (van Netten et al., 2016). This same review of interventions to prevent recurrent ulcers found there is strong evidence for self-management and footwear interventions but weak evidence for other interventions. A recent Cochrane systematic review (McGloin et al., 2021) also highlighted the limited psychological interventions that currently exist for patients with DFU and the need for more robust studies in this area. Building on this research, the proposed scoping review is being conducted to: 1) Investigate the emotional consequences and burdens of living with DFUs, and; 2) Examine how psychosocial factors influence the progression and management of ulcerations. The review is being conducted as part of a PhD project. Findings from this review, and subsequent qualitative studies, will inform the development of a psychological intervention that will aim to enhance psychosocial functioning and reduce the progression and recurrence of foot ulcers.

A scoping review methodology was selected for this study as this methodology will allow synthesis and appraisal of the wider evidence-base, including non-RCT designed studies. In addition, a scoping review was deemed to be the most suitable methodology for this review for the following reasons:

1. The exploratory nature of the topic

The interplay between psychological factors and DFUs is a relatively underexplored area. A scoping review allows for the exploration of a wide range of psychological aspects, including depression, anxiety, stigma, and coping mechanisms, rather than focusing narrowly on a specific question. A scoping review is also considered the most appropriate methodology to broadly map the key sources and types of evidence available on the area of interest, and identify gaps for further research, when the extent and nature of the research is largely unknown (Arksey & O'Malley, 2005; Pham et al., 2014).

2. Identifying Research Gaps

A scoping review can systematically identify gaps in the current literature regarding psychological factors affecting DFUs. This is critical for guiding future research directions, which is particularly beneficial for a PhD study, such as this, that is aiming to contribute original insights to the field. It can also reveal which psychological factors are well-researched and which are neglected, allowing the researcher to focus their PhD on the most pertinent and impactful areas.

3. Inclusion of Diverse Study Designs

A scoping review allows for the inclusion of different types of studies (qualitative, quantitative, mixed-methods), which is essential in a complex area like psychological health. This flexibility can provide richer insights into how psychological factors impact DFUs. By synthesizing various research methodologies, the review can offer a comprehensive understanding of the psychological dimensions affecting patients with DFUs.

4. More flexible than Systematic Reviews

Scoping reviews do not require the same level of stringent inclusion/exclusion criteria as systematic reviews, allowing for a more flexible approach to literature inclusion. This is particularly useful in a field where studies may vary significantly in focus and methodology.

In summary, this research is being carried out with a scoping review methodology, rather than as a systematic review, due to the exploratory nature, capacity to identify research gaps, flexibility in study inclusion, and ability to synthesize diverse forms of evidence. This methodological approach will offer a comprehensive foundation for understanding the psychological dimensions of DFUs and will effectively guide future research initiatives.

Principal terminology definitions

Complex wound: In recent years, chronic wounds have been described as “complex wounds,” in order to represent the multifactorial dynamic tissue healing process that is involved (Hall et al., 2014; Labib & Winters, 2023). For a wound to be classified as a complex wound, it must show one of the following features (Ferreira et al., 2006): 1) Persistent for more than three months; 2) Compromised vascularity or necrosis; 3) Presence of infection; 4) Associated comorbidities impair healing potential.

Diabetes-Related Foot Ulcer (DFU): A diabetes-related foot ulcer (DFU) has been defined as a break in the skin of the foot of a person with diabetes, which penetrates as a minimum to the epidermis and part of the dermis (McDermott et al., 2023). DFUs are classified as neuropathic, ischemic, or neuro-ischemic based on their underlying causes e.g. whether they are caused by systemic factors such as hyperglycemia or immune dysfunction or by local factors such as pressure or trauma (Jeffcoate et al. 2024). Additionally, DFUs can be categorized by severity using classification systems such as SINBAD (IWGDF, 2023). Systems such as this assist healthcare providers in predicting patient outcomes and determining the most appropriate treatment strategies.

Wound healing: A healed wound or complete wound closure can be defined as 100% re-epithelialization of the wound without drainage (Armstrong et al., 2020). For an individual with diabetes, several biological elements can adversely affect ulcer healing including persistent and impaired inflammation, loss of protective sensation, motor neuropathy causing abnormal biomechanics, peripheral arterial disease, and infection (Rayman et al., 2020). Systemic factors such as age, sex, stress levels, medication (steroids, NSAIDs), alcohol use, and diet may also impact wound healing (Chhabra et al., 2017). The management of a DFU is thus particularly challenging and proper wound care (such as cleaning the wound, keeping it moist, and protecting it from further injury or infection) is critical to facilitate healing. The management of lifestyle factors, blood sugar levels, infection, and other underlying medical conditions is also essential for successful healing of DFUs (Alexiadou & Doupis, 2012). This review will be looking at wound healing in relation to the impact that psychological factors have on management, progression and reoccurrence.

DFU Reoccurrence: A new foot ulcer in a person who has a history of foot ulceration, irrespective of location and time, since previous foot ulcer (IWGDF, 2023) This review will be looking at the role that emotional and psychosocial factors may play in the recurrence of a DFU.

Emotional wellbeing. Emotional wellbeing refers to a person's overall mental and emotional state of being, characterized by the ability to manage and regulate emotions, cope with stress and adversity, and experience a sense of life satisfaction and overall psychological functioning (Huppert & So, 2013). This review will be looking at the impact that living with a DFU has on emotional wellbeing.

Psychosocial wellbeing. Psychosocial wellbeing refers to the combination of psychological and social factors that contribute to an individual's overall sense of well-being (Eisenberg et al., 2007). Encompassing an individual's mental, emotional, social, and spiritual well-being, psychosocial wellbeing can be impacted by a variety of internal and external factors such as cultural and societal norms, physical health, economic status, personal relationships, and life experiences. This review will be looking at the impact that living with a DFU has on psychosocial functioning, and its subsequent effects on overall well-being.

Stage 1: Identifying the research question

As recommended by the Joanna Briggs Institute (2015), the PCC (Population/ participants, Concept and Context) framework was used to cultivate the research questions for this scoping review. This framework acts as a guide to facilitate the construction of a clear and meaningful title and the development of subsequent question(s) for a scoping review. For the current review, the authors are interested in individuals with diabetes-related foot ulcers (P) and exploring how living with this condition impacts their emotional and social wellbeing (C) in order to investigate the influence of psychological factors on DFU healing/ reoccurrence outcomes (C).

Research Questions

Stage 2: Identifying relevant studies

Eligibility criteria. The PCC framework used for developing the research questions will inform inclusion and exclusion criteria, and consequently the literature search strategy (Peters et al., 2020). A justification will be provided for all exclusion criteria and any given limitations that are required (Pollock et al., 2021; Tricco et al., 2018). The review will consider both qualitative and quantitative primary research in the English language and between the years 2002 and 2022, to ensure currency of content. Unpublished (grey literature) will also be included. See Table 1 for full inclusion and exclusion criteria.

Search strategy

An expert university librarian has been part of the research team from the start of this scoping review. They have assisted with designing and refining the search strategy and provided guidance on how best to adapt these terms for individual databases. This input is crucial to ensure the search strategy and results are transparent and auditable.

A three-step search strategy will be utilised for the scoping review. First, an initial search of two databases, PubMed and PsycINFO, will be undertaken, followed by an analysis of the text words contained in the title and abstract of retrieved papers. Using the PCC framework, ideas will be expanded using search terms and appropriate thesaurus terms and synonyms. A second search using all identified keywords and index terms will then be undertaken across all included databases. Databases to be searched include the Cochrane Database of Systematic Reviews, OVID (Medline), EMBASE (Elsevier), CINAHL (EBSCO), PsycINFO (EBSCO), SCOPUS and Web of Science Core Collection. Thirdly, the reference lists of identified reports and articles will be searched for additional sources. A search for grey material will also be carried out within ProQuest E-Thesis Portal, and Lenus. See Table 2 for search strategy development.

Stage 3: Study selection

Screening for this review will be conducted within Covidence, a systematic review data management system https://www.covidence.org/ (Covidence, 2019). Covidence is a core component of the Cochrane review production toolkit and has also been endorsed by the Joanna Briggs Institute. An open access alternative such as Rayyan (https://www.rayyan.ai/) could also be used.

Pilot testing will be conducted prior to embarking on source selection. This will involve the research team selecting a sample of 25 titles and abstracts at random and two members (MH and EK) independently screening them using the pre-defined eligibility criteria and definitions. The team will then meet and if any discrepancies have been identified these will be discussed and modifications will be made to the eligibility criteria and definitions if required. Screening will start once an agreement rate of 75% (or greater) is achieved. Using the pre-specified inclusion and exclusion criteria, two reviewers will independently screen each title and abstract. A third independent reviewer will be consulted and make the final decision regarding inclusion if consensus is not reached between the two reviewers.

The process of study selection will be reported using a PRISMA flow diagram (Tricco et al., 2018), which will then be updated once the review is completed.

Stage 4: Charting the data

The research team will design a data charting tool, as set out by the PRISMA-ScR Checklist (Tricco et al., 2018), to which the following information will be extracted by two members of the research team:

To ensure that the coding framework is consistently applied, two team members will pilot test the charting table by using a sample (10%) of the complete list of retrieved studies that are to be included. If necessary, modifications to the categories and revisions to the charting table may occur at this stage. Any discrepancies or queries that emerge from the pilot will be discussed by the full team before going ahead with the data extraction process. During this iterative process, the authors are aware that the charting tool may also need to be adjusted to ensure accurate representation of all data sources.

Stage 5: Collating, summarising, and reporting of results

A PRISMA flow diagram will be used to visually represent study selection and reasons for exclusion at full text review. Presentation of the results will be in a visual and aggregate form (e.g., using charts and tables), as well as a descriptive format aligning to the objectives and scope of this review.

Step 6: Consultation with stakeholders

In order to identify any further references and studies that should be included and to gather feedback regarding the scoping review findings, the Arksey and O’Malley framework proposes an optional sixth step that involves consulting with key stakeholders. The authors of this paper believe this to be a very worthwhile and valuable exercise as it will ensure that the search strategy includes all relevant and appropriate terms and will enhance the relevance of the research overall by gathering feedback on the content. A stakeholder group that included multidisciplinary team members and external collaborators were thus consulted in advance of beginning this review. The group consisted of an independent patient representative (DNN), a clinical psychologist (AD), a podiatrist (VB), a health researcher (HD), and an endocrinologist (KD).