Prevalence of diabetic foot complications in the West of Ireland: A pilot study
Diabetic foot ulcers, Service development and delivery | Sarah Kelly, Catherine Dolan, Lorna Hurley, Laura Kelly, Adam Garrow, Eamonn O’Shea, Liam Glynn, Sean Dinneen
The incidence of diabetic foot complications in the Republic of Ireland is not known. A cross-sectional pilot study was undertaken to identify the prevalence of diabetic foot complications in a primary care setting in the west of Ireland, and to inform the design and feasibility of a larger community-based diabetic foot screening study in Ireland. Clinically important pedal neural dysfunction was detected in up to 30% of those screened, and vascular impairment was detected in some 17%.
Page (1) Points
- The present study is a cross-sectional pilot designed to identify the prevalence of diabetic foot complications in a primary care setting in the west of Ireland
- Neural and vascular dysfunction of the foot were detected in up to 30% and 17% of participants, respectively
- Based on this pilot, a protocol was developed for the West of Ireland Diabetes Foot Study, a 3-year prospective study on the incidence, cost and feasibility of screening for diabetic foot complications
Foot complications are considered to be the most costly diabetes-related complication, accounting for up to 20% of total healthcare resources available for diabetes in developed countries (International Diabetes Federation [IDF], 2009). A study carried out at St James Hospital, Dublin, reported that annual hospital expenditure on the treatment of diabetic foot ulceration amounted to €704 000 (Smith et al, 2004).
The prevalence of diabetes in the Republic of Ireland is estimated to be 4.7% of the population (Institute of Public Health in Ireland, 2006), but the condition's true prevalence is not known. Likewise, the true prevalence of diabetic foot complications in Ireland is not known. Current national and international guidelines (NICE, 2004; IDF, 2009; SIGN, 2010) recommend that people with diabetes should receive a comprehensive annual foot examination. Diabetic foot screening in the primary care setting is not routinely undertaken in Ireland.
The present study is a cross-sectional pilot, designed to identify the prevalence of diabetic foot complications in a general practice population in the west of Ireland. This pilot study was undertaken to inform the design and feasibility of a large community-based diabetic foot screening study in the west of Ireland.
People (≥18 years of age; with type 1 or 2 diabetes) on the diabetes register of an urban general practice in the west of Ireland were invited to attend a foot screening examination. A letter was sent by the research team inviting them to make a foot screening appointment at the Community Podiatry Department, Primary Community and Continuing Care, Health Services Executive West.
This study was approved by the Research Ethics Committee of the Irish College of General Practitioners. All participants provided written consent to undergo foot screening.
Screening was undertaken by two medical students under the supervision of a community podiatrist. Individual screening assessments took approximately 15 minutes. The sensory and vascular tests used for screening were selected based on a review of the literature, international guidelines and consultation with experts in the field.
Tests performed to assess pedal sensory perception were: (i) a 10-g monofilament; (ii) the modified neuropathy disability score (mNDS); and (iii) a vibration perception threshold test. These tests, and the normal range for results, are described in Box 1.
Vascular assessment comprised bilateral palpation of dorsalis pedis and posterior tibial pulses and measurement of the ankle-brachial pressure index (ABPI). A participant history was taken to determine if the participant had experienced intermittent claudication, indicating vascular insufficiency.
If two of the four pedal pulses were impalpable, the result was deemed abnormal (Abbott et al, 2002). An ABPI <0.9 was considered abnormal, and >1.3 was considered significantly elevated and indicative of vascular calcification (Boulton et al, 2008).
Results of the screenings are shown in Table 2.
Neuropathy was detected in between 19% (3/16, detected by the vibration perception threshold test) and 30% (9/30, detected by a 10-g monofilament) of participants. Evidence of vascular impairment, based on pedal pulse palpation, was found in 17% (5/29) of participants. The average ABPI among the participants in whom it was recorded (n=22) was 1.12 (range, 0.95-1.37).
Some technical difficulties were encountered during the screening process. While the 10-g monofilament, mNDS and pedal pulses were recorded for ≥97% (29-30/30) of participants, ABPI and vibration perception threshold tests were less uniformly carried out with success.
Problems encountered using the ABPI were possibly related to non-compressible vessels and the use of an automated sphygmomanometer. An ABPI was reported for only 73% (22/30) of participants. The neurothesiometer was not available to the clinicians carrying out the screening at all times, resulting in only 53% (16/30) of participants being scored for the vibration perception threshold test.
Data from this pilot study indicate that a sizeable number of people with diabetes attending an urban general practice in the west of Ireland have vascular insufficiency and abnormal measures of neural function in their feet. These findings are of concern given the associations between lower-limb vascular insufficiency, neuropathy and increased risk of ulceration (Nather et al, 2008).
It is interesting to compare the data presented here, with those of a large UK-based cohort - the North-West Diabetes Foot Care Study (Abbott et al, 2002). Abbott et al report foot screening of 9700 people with diabetes.
The North-West Diabetes Foot Care Study found that 21% of participants were insensitive to a 10-g monofilament at one or more sites out of eight. The present study found that 30% of participants were insensitive to a 10-g monofilament at two or more sites out of ten. Twenty-two percent of the North-West cohort had abnormal mNDS', while 13% in the present study returned an abnormal score for this measure.
Vascular insufficiency was detected in 17% of the present cohort using pedal pulses. Twenty-one percent of the North-West cohort were recorded as having abnormal pedal pulses.
Page (2) Points
- The neurothesiometer for vibration perception threshold testing was not available to the clinicians carrying out the screening at all times
- The North-West Diabetes Foot Care Study found that 21% of participants were insensitive to a 10-g monofilament, in the present study the figure was 30%
- Based on this pilot, a protocol was developed for the West of Ireland Diabetes Foot Study, a 3-year prospective study on the incidence, cost and feasibility of screening for diabetic foot complications in this population
Discrepancies between the results reported by Abbott et al (2002) and those in the present study may reflect a number of population, sampling and instrument variations. The present cohort was smaller than that reported by Abbott et al (2002). There may have been differences in the techniques used by the screening clinicians, or measurement errors may have occurred. Results from the present study suggest that estimates of vascular and neurological dysfunction are likely to vary depending on the methods of screening used.
The West of Ireland Diabetes Foot Study
Although the present cohort was small, this pilot proved informative for the development of a larger foot screening study. Based on this pilot, a protocol has been developed for the West of Ireland Diabetes Foot Study, a 3-year prospective study on the incidence, cost and feasibility of screening for diabetic foot complications in this population. Funded by the Diabetes Federation of Ireland and the Health Research Board, this study aims to recruit 560 people with diabetes from approximately 12 general practices in Counties Galway and North Clare to be involved in a foot screening programme.
Practice and public health nurses from participating practices will be invited to attend a foot-screening workshop on vascular and neurological assessment of the foot. With the support of a podiatrist, people with diabetes from these practices will be invited to attend a foot screening, with appropriate follow-up and specialist referral as necessary.
The study will determine the prevalence of diabetic foot complications in this population. In addition, the effectiveness of commonly used screening tools - assessed both as individual items and in combinations - will be assessed to develop a standardised, effective method of foot screening.
An additional aim of the West of Ireland Diabetes Foot Study will be to look at aspects of health economics relating to the diabetic foot. The cost of new episodes of diabetic foot ulceration in the study population will be calculated prospectively.
It is hoped that the findings of the West of Ireland Diabetes Foot Study will support the development of an evidence-based protocol and integrated care pathway for the management of diabetic foot disease. From a service development standpoint, the study should equip participating practice staff with the knowledge and skills to perform diabetic foot screening within their practice. The study will have implications for the delivery of routine diabetes care in the west of Ireland.
Page (5) Points
- The West of Ireland Diabetes Foot Study will look at aspects of health economics related to the diabetic foot
- It is hoped that the findings of the West of Ireland Diabetes Foot Study will support the development of an evidence-based protocol and integrated care pathway for the management of diabetic foot disease
- Podiatry input is critical to proper management of the diabetic foot and it is hoped that the new NUI Galway podiatry honours degree programme will ensure a regular supply of podiatrists for the Irish Health Service
- This pilot highlights the need for diabetic foot screening in the community setting
In the absence of a formal foot screening initiative, it is likely that people at risk of foot ulceration go unrecognised. Yet, the clinical skills for diabetic foot screening are not elaborate, and are likely to be within the scope of a well-informed and well-trained practice team. Prerequisites for such a programme are the development of a diabetes register in the practice (not all practices in Ireland have such a register [Evans et al, 2009]), training of practice staff in foot screening and remuneration for the delivery of preventive services within the GP contract.
The Department of Health and Children, the Irish College of General Practitioners and the Irish Endocrine Society have published joint guidance on type 2 diabetes care (Harkins, 2008). The importance of diabetic foot screening was highlighted and a useful protocol for the classification and management of the diabetic foot provided. The guidance recommends that foot screening be undertaken by members of the practice team.
Podiatry input is critical to proper management of the diabetic foot. The Diabetes Expert Advisory Group First Report (Health Service Executive, 2008) reveals that Ireland has the lowest manpower in podiatry for diabetes in Europe, with only two full-time posts in the whole country. In 2002, the Diabetes Federation of Ireland published region-by-region data on the manpower deficit and estimated that two full-time diabetes podiatrists are needed per 100 000 head of population in Ireland. Thus, some 90-100 full-time podiatrists are required to assess and manage diabetes-related foot complications.
In September 2008, the NUI Galway opened its doors to its first cohort of podiatry students undertaking a 4-year honours degree programme. Until the graduation of this class, Ireland will - as it has in the past - rely on UK-trained podiatrists. It is hoped that NUI Galway's School of Podiatry programme will ensure a regular supply of podiatrists for the Irish Health Service. It is incumbent on the Irish Health Service Executive to develop a podiatry manpower plan so that these new podiatry graduates can support the formation of multidisciplinary diabetic foot care teams in Ireland.
This pilot highlights the need for diabetic foot screening in the community setting. Results from the forthcoming West of Ireland Diabetes Foot Study will provide further data on the incidence of diabetic foot complications in this population, and the role of primary care clinicians in screening and risk assignment. It is hoped that diabetic foot screening in the primary care setting in Ireland will shift the burden of diabetic foot care away from episodes of end-stage, complex, expensive ulceration and amputation, and towards early intervention and prevention.
The authors would like to thank Patricia Godwin (Podiatry Manager, Primary Community and Continuing Care, Health Services Executive West, Galway) and Caroline McIntosh (Head of School of Podiatry, NUI Galway, Galway) for their assistance.
Sarah Kelly and Catherine Dolan are Junior Doctors, both are based at the Department of Medicine, NUI Glaway, Galway; Lorna Hurley is a Community Diabetes Facilitator and Laura Kelly is a Senior Podiatrist, both are based at the Diabetes Day Centre, University Hospital Galway and the Primary Community and Continuing Care, Health Services Executive West, Galway; Adam Garrow is a Research Podiatrist and Epidemiologist, Centre for Social Justice Research, University of Salford, Salford; Eamonn O'Shea is a GP, Department of General Practice, NUI Galway, Galway; Liam Glynn is a Lecturer in Primary Care, Department of General Practice, NUI Galway, Galway; Sean Dinneen is a Consultant Endocrinologist and Senior Lecturer in Medicine, Department of Medicine, NUI Glaway and Diabetes Day Centre, University Hospital Galway, Galway.
Abbott CA, Vileikyte L, Williamson S et al (1998) Multicenter study of the incidence of and predictive risk factors for diabetic neuropathic foot ulceration. Diabetes Care 21: 1071-5
Abbott CA, Carrington AL, Ashe H et al (2002) The North-West Diabetes Foot Care Study: incidence of, and risk factors for, new diabetic foot ulceration in a community-based patient cohort. Diabet Med 19: 377-84
Boulton AJ, Armstrong DG, Albert SF et al (2008) Comprehensive foot examination and risk assessment. A report of the Task Force of the Foot Care Interest Group of the American Diabetes Association, with endorsement by the American Association of Clinical Endocrinologists. Phys Ther 88: 1436-43
Evans DS, O'Connell E, O'Donnell M et al (2009) The current state of general practice diabetes care in the West of Ireland. Practical Diabetes International 26: 322-5
Garrow AP, Boulton AJ (2006) Vibration perception threshold - a valuable assessment of neural dysfunction in people with diabetes. Diabetes Metab Res Rev 22: 411-9
Harkins, V (2008) A Practical Guide to Integrated Type 2 Diabetes Care. Department of Health and Children, Irish College of General Practitioners, Irish Endocrine Society, Dublin
Health Service Executive (2008) Diabetes Expert Advisory Group First Report: April 2008. HSE, Naas. Available at: tinyurl.com/y8ptjf6 (accessed 01.04.10)
Institute of Public Health in Ireland (2006) Making Diabetes Count: A Systematic Approach to Estimating Population Prevalence on the Island of Ireland in 2005. IPHI, Dublin. Available at: tinyurl.com/ycj8gon (accessed 01.04.10)
International Diabetes Federation (2009) Position Statement - The Diabetic Foot. IDF, Brussels. Available at: tinyurl.com/ye2kouy (accessed 30.03.10)
Nather A, Bee CS, Huak CY et al (2008) Epidemiology of diabetic foot problems and predictive factors for limb loss. J Diabetes Complications 22: 77-82
NICE (2004) Type 2 Diabetes: Prevention and Management of Foot Problems. Clinicial Guidance 10. NICE, London. Available at: tinyurl.com/ydewb9n (accessed 01.04.10)
Scottish Intercollegiate Guidelines Network (2010) Management of Diabetes: A National Clinical Guideline 116. SIGN, Edinburgh. Available at: tinyurl.com/ybd7md4 (accessed 01.04.10)
Singh N, Armstrong DG, Lipsky BA (2005) Preventing foot ulcers in patients with diabetes. JAMA 293: 217-28
Smith D, Cullen MJ, Nolan JJ (2004) The cost of managing diabetic foot ulceration in an Irish hospital. Ir J Med Sci 173: 89-92
Young M (2008) A perfect 10? Why the accuracy of your monfilament matters. The Diabetic Foot Journal 11: 106-11
Young RJ, Zhou YQ, Rodriguez E et al (1986) Variable relationship between peripheral somatic and autonomic neuropathy in patients with different syndromes of diabetic polyneuropathy. Diabetes 35: 192-7
Young MJ, Boulton AJ, MacLeod AF (1993) A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population. Diabetologia 36: 150-4
Young MJ, Breddy JL, Veves A, Boulton AJ (1994) The prediction of diabetic neuropathic foot ulceration using vibration perception thresholds. A prospective study. Diabetes Care 17: 557-60