NDFA Interval Review: July 2014-March 2021

Background

There are 106 clinical commissioning groups (CCGs) in England and 7 local health boards (LHBs) in Wales. NDFA data have been provided by a total of 138 NHS trusts, 6 LHBs and 16 independent healthcare providers (IHPs).

Incidence of new ulcer episodes

The number of new foot ulcers in people with diabetes in England and Wales is not certain. Data from Lancashire in 2002 suggested that the incidence was just over 2 per 100 person years (Abbott et al, 2002) but more recent data from Scotland (Chamberlain et al, 2021) suggested that the current figure may be closer to 1 per 100 person years.

Findings

NDFA data between April 2018 and March 2021 show wide ranging registration rates by CCG/LHB from 0.0 to 1.9 per 100 person years (see Appendix 5.1, below). These data suggest that while many CCG/LHBs were gathering information on nearly all new foot ulcers over the 3 year period, many others were not.

Appendix 5.1: NDFA ulcer registration rates per 100 person years for people with diabetes, by commissioner, England and Wales, 2018-21

Findings

Since 2014-15 the proportion of ulcer episodes that are self-referred has increased from 30% to 35% in 2019-20, before reducing slightly to 33% in 2020-21 (see Appendix 5.2a, below).

The proportion of ulcer episodes seen within 13 days has increased from 43% to 46% (Appendix 5.2a) and from 61% to 69% where self-referrals are excluded (Appendix 5.2b).

Appendix 5.2: Time to FEA, England and Wales, 2014-21

Findings

Since 2014-15: The percentage of severe ulcers fell steadily from 48% in 2014-15 to 42% in 2019-20. There was a small rise to 43% in 2020-21 possibly related to the COVID-19 pandemic (see Appendix 5.3a, below).

Similar trends are evident when self-referrals are excluded from the denominator (Appendix 5.3b), with severe ulcers falling from 52% to 48%.

Appendix 5.3: Ulcer severity at FEA, England and Wales, 2014-21

Findings

Severe ulcers are less likely to be healed at 12 weeks: 35% alive and ulcer-free (severe) vs 61% (less severe). Both severe and less severe ulcers show improvements in healing up to 2019-20: 59% to 61% (less severe), 34% to 37% (severe). There was a small drop in healing in 2020-21 (2 percentage points), coinciding with the COVID-19 pandemic.

Appendix 5.4: Ulcer status at 12 weeks after FEA (excludes unknown outcomes), England and Wales, 2014-21

Findings

The NDFA has consistently found that:

There has been no major change over time in the relationship between the 4 groups.

Appendix 5.5: Percentage severe ulceration at FEA, by time to FEA, England and Wales, 2014-21

Findings

There has been a steady increase in co-morbidities in the population registered with the NDFA – as reflected in hospital admissions for heart failure recorded in the year before ulcer presentation (Appendix 5.6a, below).

All 3 cardiovascular conditions in Appendix 5.6b are associated with 12-week mortality (see NDFA 2019, p.47, 77-79) and will have an impact on the recorded incidence of ulcer healing at 12 weeks.

Update 15 August 2022.  Appendices 5.6a and 5.6b have been updated after an error was identified in the analysis code. The corrected figures for 5.6a still show a steep increase in heart failure, but rates of myocardial infarction and stroke are now flat, rather than upward. Updated figures for 5.6b are similar to those previously published.

Appendix 5.6: Hospital admissions in year prior to FEA, England and Wales, 2014-21

Background

Providers have been grouped into 9 English regions, plus Wales as a whole.

The percentage of people reported as alive and ulcer-free at 12 weeks is shown by region, split by ulcer severity.

Findings

12-week healing rates vary across regions, from 48% to 68% for less severe ulcers and 27% to 41% for severe ulcers.

Appendix 5.7: Percentage of people alive and ulcer-free at 12 weeks after FEA, by region (excludes unknown outcomes), England and Wales, 2014-21

Background

For each provider (NHS trust, LHB or IHP), the expected number of severe ulcer episodes to be healed at 12 weeks was calculated using the England and Wales average. Expected numbers were then compared to the actual numbers, to produce a healing ratio (HR) where 100 = exactly as expected.

Control limits (2 and 3 standard deviations, SD) were used to assess whether the HR for a provider is within an expected range above or below 100.

Findings

10 of 129 (8%) providers have higher than expected unadjusted healing rates for severe ulcers (above 3SD).

13 of 129 (10%) have lower than expected healing rates for severe ulcers (below 3SD).

Appendix 5.8: Unadjusted healing ratios: Alive and ulcer-free at 12 weeks after FEA: Severe ulcers by provider, (excludes unknown outcomes), England and Wales, 2014-21

Background

Lower limb amputation is the surgical excision of bone and soft tissue of the foot or leg. Major amputation (above the ankle) is carried out when it is judged that the lower leg cannot be saved.

Findings

Overall, this time series reveals no change in the incidence of major amputation observed within 6 months of FEA – which remains around 0.6% for less severe ulcers and around 2.7% for severe ulcers.

The 4th NDFA report (2019) identified severe ischaemia, involvement of the heel, older age, smoking and renal disease as particular risk factors for major amputation (1).

Appendix 5.9: Percentage of people having major amputation within 6 months of FEA, England and Wales, 2014-21

Notes: (1) NDFA (2019) p.46, 73-75.

Background

Providers in England and Wales have been grouped by region.

The percentage of severe ulcer episodes where major amputation was undertaken within 6 months of FEA is shown by region.

Findings

Regionally, major amputation rates at 6 months in people presenting with severe ulcers vary from 1.8% to 3.6%.

Regional trends over time are shown in Appendix 5.12, uploaded as a separate document.

Appendix 5.10: Percentage of people having major amputation within 6 months of FEA: Severe ulcers, by region, England and Wales, 2014-21

Background

A new, alternative NDFA outcome measure is major amputation-free survival. This is assessed at 1 year after FEA.

Equivalent data for earlier years are not available. Audit year 2020-21 is excluded because the data for the full year follow-up period was not available when the analysis was prepared.

Findings

90% of those presenting with less severe ulcers were alive and major amputation-free at 1 year (Appendix 5.11a), compared with 82% of those with severe ulcers (Appendix 5.11b).

87% of cases where major amputation-free survival was not achieved were a result of death within 1 year. The remainder (13%) were the result of major amputation within 1 year.

Appendix 5.11: 1 year major amputation-free survival: Less severe ulcers, Severe ulcers, England and Wales, 2018-20

Notes: (1) 1 year from FEA.