Patients With Infected Diabetic Foot Ulcers Need Quick Referral

Liam Davenport

November 20, 2017

Patients with an infected diabetic foot ulcer have a far worse prognosis than previously thought, with 15% of patients dying within a year, less than half of the ulcers healing in the same time period, and one in seven individuals having all or part of their foot amputated, results from a new UK study reveal.

The analysis of almost 300 patients with infected diabetic foot ulcers also showed that, even if the ulcer healed, nearly 10% experienced a recurrence within 12 months and more than 25% of patients underwent some kind of procedure.

It's therefore crucial that such patients are reviewed quickly and referred for specialist care if required, say Mwidimi Ndosi, PhD, of the University of West Bristol, United Kingdom, and colleagues in their paper published online November 20 in Diabetic Medicine.

"The key point is that people need to be seen quickly if an ulcer begins to form; that gives health workers the greatest chance of trying to treat the condition," stresses coauthor Michael Backhouse, PhD, a podiatrist and senior research fellow at the University of Leeds, United Kingdom, in a press release from his institution.

These latest data "should be useful to clinicians in various care settings to help identify people most at risk of poor outcomes who may need prioritization for increased interventions or referral to specialist centers," the scientists say.

Ischemia, Many Ulcers, and Longer Ulcer Duration Predictive of Poor Outcomes

For the analysis, the researchers performed a 12-month prospective observational assessment, via detailed review of case notes, of 250 patients with diabetes who had participated in the Concordance in Diabetic Foot Ulcer Infection (CODIFI) study and were still alive at the end of that, in May 2013. They also include 49 participants from the trial who had died but for whom clinical data were available.

The mean age of the patients was 64.3 years, and 233 (77.9%) were male.

After 12 months of further follow-up, the index ulcer had healed in a total of 136 (45.5%) of the 299 patients, while 13 (9.6%) had a recurrence.

Fifty-two (17.4%) of patients had amputation of some part of the foot during follow-up, 18 (6.0%) underwent peripheral revascularization, and 10 (3.3%) underwent both procedures.

And a further 45 (15.1%) patients had died by the 12-month cutoff.

The median time to healing of the index ulcer was 4.5 months, while median time to amputation, if this occurred, was 2.0 months, and for revascularization, it was 3.0 months.

For those who didn't survive, the average time to death was 5.6 months.

Presence of limb ischemia, multiple foot ulcers, and a longer ulcer duration were most predictive of poor 12-month outcomes.

For example, those with an ulcer present for 2 months or more prior to enrollment in CODIFI had a lower chance of it healing, at a hazard ratio (HR) of 0.55, as did those with a perfusion, extent, depth, infection, sensation (PEDIS) grade in the index ulcer of ≥2, indicating peripheral arterial disease; this reduced the risk of healing by 63% (HR, 0.37).

Conversely, having only one ulcer on the index foot was associated with an increased risk of healing of 90% [HR, 1.90], as was the identification of coagulase-negative staphylococci on the ulcer culture (HR,  1.53); most likely, say the researchers, because presence of this organism was inversely related to the presence of the more virulent MRSA.

Amputations to Be Avoided Where Possible

Diagnosing whether or not a diabetic foot ulcer is infected can be difficult, especially in the presence of limb ischemia or peripheral neuropathy, the researchers note, but it is generally agreed that this decision should be based on signs or symptoms of inflammation or purulence.

Senior author E Andrea Nelson, PhD, RGN, head of the School of Healthcare in the Faculty of Medicine and Health, University of Leeds, told Medscape Medical News that the cohort they recruited was representative of the overall National Health Service patient population in England, and the study had very few exclusion criteria, so she believes the data will be broadly applicable to populations with infected diabetic foot ulcers in other Western countries.

Dr Nelson emphasized that patients who undergo amputations generally have a lower quality of life than those who avoid this outcome and that having one amputation indicates a higher likelihood of a subsequent amputation because it signifies a poor vascular supply.

Moreover, she noted that amputations are costly, in terms of the time patients have to spend in the hospital, the cost of hospital care, rehabilitation and prostheses, etc, and the postamputation care required.

She said the ideal is to provide care that minimizes the amputation rate in patients with diabetic foot ulcers.

Nevertheless, amputation "is not something that you would avoid at all costs, because to have, for example, a toe amputation might avoid further, more extensive harm for the patient."

As well as helping doctors in various settings to identify those who may need prioritization, these new findings "should also be useful to inform the design and analysis of future clinical studies," the researchers conclude.

The research was funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) program. Dr Nelson was a member of the HTA Commissioning Board. The coauthors have no relevant financial relationships.

Diabet Med. Published online November 20, 2017. Abstract

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