Diabetic foot ulcers (DFUs) are a cause of considerable suffering and cost to the NHS – approximately £1 billion, 0.8% of the total NHS budget (Diabetes UK, 2017). Although some care outcomes have improved enormously in the last 20 years, with the annual incidence of major amputation in people with diabetes in the UK falling from about 3.5 to 0.8 per 1000 people, there is still evidence of wide geographical variation.
What is the NDFA?
The National Diabetes Footcare Audit (NDFA) in England and Wales was established in July 2014 and is one of a family of national audits that are now linked to the National Diabetes Audit (NDA). It seeks to include all newly occurring DFUs, to measure aspects of care against NICE (2015) standards and to link these with clinical outcomes. The aim is to support efforts to reduce variation in care and to improve outcomes overall.
What data are collected?
The information gathered specifically for the NDFA is in two parts: (a) three questions on the structure of care, which are submitted annually to every Clinical Commissioning Group (CCG) in England and Local Health Board (LHB) in Wales; and (b) three simple items that foot service clinicians (usually podiatrists) record for each new DFU case. The details of these are presented in Box 1 and Box 2 (overleaf). It should be noted that, rather than collect data on DFU healing or amputation, the single, patient-centred outcome measure chosen is a composite of survival and being ulcer-free.
The burden of data capture is deliberately kept low in order to (a) increase involvement in the audit; (b) reduce the likelihood of cases being selected for registration on the basis of ease of completing the form; and (c) minimise the collection of data that may be of uncertain validity. Demographic and other clinical details are available from linkage to the NDA and to the Hospital Episode Statistics/Patient Episode Database for Wales (HES/PEDW).
Who collects the clinical data?
The NDFA encourages involvement from any healthcare professional who assumes care of a DFU at any stage of the care pathway. The possibility of multiple entries being received for any one episode is eliminated by use of the patients’ NHS numbers.
Preliminary findings from 14 July 2014 to 8 April 2016
The most recent report was published online on 8 March 2017 and includes data from the first 21 months. Full details can be found at: http://digital.nhs.uk/catalogue/PUB23525.
Care structures in place
The response of CCGs (in particular) and LHBs to the 2016 questionnaire was not complete, with replies received from 110 of 209 CCGs in England and six of seven LHBs in Wales. Less than 50% of responding organisations confirmed that they had all three of the recommended structures of care (Box 1) in place. Definitive answers to all three questions were received from all six responding LHBs, but only from 77 CCGs.
Process of care
A total of 155 clinical services in England and 18 in Wales participated in the NDFA processes and outcomes audit, involving at least one team from 107 NHS Trusts in England and from all seven LHBs in Wales.
The first 21 months of audit included 13 034 newly occurring ulcers. The total number of DFUs that would have occurred in England and Wales over this period is not known but, even if this sample represents only a fraction of the total, this is by far the largest cohort of DFUs ever studied in which data have been prospectively collected.
Population
Patient demographics were as expected: the mean age was 67 years, 70% were male, the mean diabetes duration was 15 years and the majority of patients were of white ethnicity (92%), with DFUs being relatively uncommon in South Asian people despite the high prevalence of type 2 diabetes in this population.
Relationship between time to referral and ulcer severity at assessment
The ulcers were graded on the Site, Ischaemia, Neuropathy, Bacterial infection, Area and Depth (SINBAD) score as severe (i.e. more limb-threatening) in 46% of cases. People who had had an ulcer for >2 months before being assessed by the team registering the case were more likely to be graded as severe than those who were seen more quickly (58% vs 34–51%).
Outcome data and relationships with severity of ulcer at referral and time to referral
The outcome measure – being alive and ulcer-free at 12 and 24 weeks – was significantly more likely for people with less severe ulcers: 60% and 74% were alive and ulcer-free after 12 weeks and 24 weeks, respectively, compared with only 35% and 56% of those with severe ulcers. The clinical outcome was also better in those who were seen within 2 weeks of first presentation (see Figure 1).
Early analysis also suggests considerable geographic variation in outcomes. For example, the number of people with severe ulcers who were alive and ulcer-free at 12 weeks ranged from 13% to 66% between the best- and worst-performing NHS Trusts and LHBs.
Limitations of the data and conclusions
The results of the NDFA show clear associations between the time to first assessment by the team that assumed care of the DFU and both the severity of the ulcer and the chances of the person being alive and ulcer-free at 12 weeks. These associations were maintained at 24 weeks.
It is believed that this relationship is causative and that ulcers deteriorate when they are not referred quickly. NICE (2015) recommends rapid referral for all new DFUs. However, it is also possible that many less severe ulcers settle quickly in the community without any expert referral, and that the observed link between referral delay and severity simply reflects the fact that a late decision to refer was made because the ulcer was either not improving or was deteriorating. This uncertainty cannot be resolved using collated data from the whole population, but it will be possible at a later date when the total number studied is higher and more valid comparisons can be made between different areas in which referral practices differ.
It will also be possible to compare outcomes of case-mix-adjusted populations managed in different parts of the country, and this will provide further clues into which aspects of the care pathway are independently associated with outcome.
Perspective
It should not be forgotten that changes made to the structure of care over the past decades have been associated with considerable falls in the incidence of major amputation. The persisting evidence of considerable geographical variation is, however, worrying and suggests that some people are not being managed as well as they might be. This audit has the potential to help reduce both the human and the financial costs of diabetic foot disease.
NDFA developments
NHS England has directed NHS Digital to collect information for the diabetes audit programme.
From August 2017, data collection for the NDFA is mandated for providers in England, and signed consent to participate in the audit is no longer required from patients.
Patient consent is, however, still required by participating organisations in Wales.
Further information
The full 2014–2016 National Diabetes Footcare Audit (NDFA) report is available at: http://content.digital.nhs.uk
Those interested in participation should contact the NDFA via: http://content.digital.nhs.uk
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