Psychological factors and diabetic foot ulceration: a scoping review of the bi-directional relationship between diabetic foot ulcer healing and mental health factors

Rationale for this study

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; NHS: National Diabetes Foot Care Audit, 2022; International Working Group of the Diabetic Foot (IWGDF, 2019). 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. The review recognised the potential impact psychological wellbeing has on wound healing in DFU but also demonstrated that there is a dearth of RCTs in this area, which could be due to the fact that there are very few specialist psychologists working in this field. As a result of the limited number of RCTs available, there is a high risk of bias so conclusions cannot be drawn. A scoping review was thus selected for this study as this methodology will allow synthesis and appraisal of the wider evidence-base, including non-RCT designed studies. 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).

Principal terminology definitions

Diabetic Foot Ulcer (DFU). DFU is defined as an infection, ulceration, or destruction of tissues of the foot of a person with currently or previously diagnosed diabetes mellitus, usually accompanied by neuropathy and/or peripheral artery disease in the lower extremity (IWGDF, 2019).

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).

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., 2016). 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.

Behavioural factors. Behaviour refers to observable actions and processes that are initiated in response to external or internal stimuli that are received (Furr, 2009). Factors that may influence or affect human behaviour include individual characteristics (i.e., the individual’s personal disposition, ideology and belief systems, general knowledge, and personality characteristics), interpersonal factors (i.e., the individual’s relationships, social support network, and spiritual or religious relations), institutional factors (i.e., the individual may behave differently due to the rules, regulations, and informal structures that exist within the community that they reside in or the organization that they work in) and community factors (i.e., an individual’s behaviour may be directly or indirectly influenced by the available resources which they have access to in their community and the associated societal norms).

Wound healing. A healed wound or complete wound closure can be defined as 100% re-epithelialization of the wound without drainage (Armstrong et al., 2017). However, wound healing in diabetic foot ulcers is a complex process. In 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). The management of diabetic foot ulcers (DFUs) remains a challenge, thus proper wound care is critical to facilitate healing in diabetic foot ulcers. This includes cleaning the wound, keeping it moist, and protecting it from further injury or infection. Other treatment options may include debridement (removal of dead tissue), off-loading (reducing pressure on the ulcer), and various types of wound dressings or advanced therapies such as hyperbaric oxygen therapy or negative pressure wound therapy. Systemic factors such as age, gender or sex, stress levels, medication (steroids, NSAIDs), alcohol use, smoking and diet may also impact wound healing (Chhabra et al., 2017). The management of lifestyle factors, blood sugar levels, infection, and other underlying medical conditions is essential for successful healing of diabetic foot ulcers (Alexiadou & Doupis, 2012).

DFU Recurrence. A new foot ulcer in a person who has a history of foot ulceration, irrespective of location and time since previous foot ulcer (IWGDF, 2019)

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 aim to address the following research questions relating to the emotional and psychosocial implications of living with diabetic foot disease and foot ulceration:

Research Questions

Stage 2: Identifying relevant studies

Eligibility criteria. The PCC framework that was 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 thepilot 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).