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Diabetic foot ulcers

Prognosis of infected diabetic foot ulcer is worse than thought

In the first year after culture of the index ulcer, 45/299 participants (15.1%) had died., the ulcer had healed in 136 participants (45.5%), but recurred in 13 (9.6%).

The prognosis for people with an infected diabetic foot ulcer is worse than was previously thought, according to a study by researchers from the University of Leeds. More than half the patients in the research study did not see their ulcer heal over a year - and one in seven had to have part or all of their foot amputated.

Foot ulcers are open wounds and they affect around a quarter of the 3.3 million people in the UK living with diabetes and the wounds develop because diabetes damages the nerves and blood vessels in the feet. These wounds are chronic, slow to heal and prone to infection, and it is infection that normally leads to some of the severe consequences such as losing a limb or multiple amputations.

Not only do the ulcers cause disability, there are big financial implications for the NHS. The National Institute for Health and Care Excellence or NICE puts the annual cost for treating diabetic foot wounds at £650 million.

The research, led by Professor Andrea Nelson at the University of Leeds, set out to examine the outcomes for people with infected diabetic foot ulcers and the results underline the need for people at risk of foot ulcers to be closely monitored. The study, ‘Prognosis of the infected diabetic foot ulcer: a 12-month prospective observational study’, was published in the journal Diabetic Medicine.

"Foot ulcers are a very nasty condition. They're painful and are debilitating. People with foot ulcers have limited mobility, and that brings with it a whole set of other risk factors - obesity and heart disease, for example,” said Professor Nelson from the Faculty of Medicine and Health. “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."

This multicentre, prospective, observational study reviewed participants’ data at 12 months after culture of a diabetic foot ulcer requiring antibiotic therapy. From participants’ notes, the researchers obtained information on the incidence of wound healing, ulcer recurrence, lower extremity amputation, lower extremity revascularization and death. They then estimated the cumulative incidence of healing at six and 12 months, adjusted for lower extremity amputation and death using a competing risk analysis, and explored the relationship between baseline factors and healing incidence.

The researchers tracked 299 people who had attended a diabetic clinic with an infected foot ulcer, a big enough sample for it to be representative of the picture across the UK.

In the first year after culture of the index ulcer, 45/299 participants (15.1%) had died. The ulcer had healed in 136 participants (45.5%), but recurred in 13 (9.6%). An ipsilateral lower extremity amputation was recorded in 52 (17.4%) and revascularization surgery in 18 participants (6.0%). Participants with an ulcer present for  approximately two months or more had a lower incidence of healing (hazard ratio 0.55, 95% CI 0.39 to 0.77), as did those with a PEDIS (perfusion, extent, depth, infection, sensation) perfusion grade of ≥2 (hazard ratio 0.37, 95% CI 0.25 to 0.55). Participants with a single ulcer on their index foot had a higher incidence of healing than those with multiple ulcers (hazard ratio 1.90, 95% CI 1.18 to 3.06).

“Clinical outcomes at 12 months for people with an infected diabetic foot ulcer are generally poor. Our data confirm the adverse prognostic effect of limb ischaemia, longer ulcer duration and the presence of multiple ulcers,” the authors concluded.

"The results of our study are important and should help clinicians caring for patients with diabetes to identify those most at risk for poor outcomes so that we can look to provide further support," said Dr Michael Backhouse, a podiatrist and Senior Research Fellow at the University of Leeds.