The focus of this commentary is a paper by Engberg at al (2019) from Denmark, examining the incidence characteristics of recurrent or new ulcers in a cohort of healed diabetic foot ulcers. This is a retrospective study that included 780 patients followed up for a mean duration of 1.04 years between 2010–2016. For the purpose of this study, a recurrent ulcer was defined as one occurring at the same ulcer site/location and a new ulcer as one at a different location. An ulcer was deemed healed once completely epithelialised and remained intact for two consecutive clinic visits. The length between clinic visits for healed ulcers was 1–3 months. Ulcers were classified as either neuropathic (N), neuro-ischaemic (N/I) or critically ischaemic (CI). This was defined as: N: foot pulses present and vibration threshold ≥25; N/I: toe pressure 40–70 mmHg and/or ankle brachial index 75 mmHg and vibration threshold ≥25 V; and CI: toe pressure <40 mmHg and/or ankle pressure <75 mmHg. Other baseline and follow-up data collected included age, sex, diabetes duration, control (HbA1c) and type (1 or 2), cigarette smoking, body mass index, blood pressure (mmHg), renal function and physical activity.
This study showed that a third (33.1%) developed a recurrent/other new diabetic foot ulcer per year but, interestingly, 77% of these were new ulcers not ulcer relapses. Healed ulcers strangely predominately occurred the toes (60%) with only 15% occurring on the plantar surface irrespective of N, N/I or CI. The sites for new or relapse ulcers was not given but occurred more commonly in males, type 2 diabetes and smokers. Patients with N/I or CI diabetic foot ulcers were statistically more likely to ulcerate than those with neuropathy.
The paper sheds no light upon prevention strategies employed so it is difficult to comment upon confounding variables. It may be possible that any neuropathic relapse ulcers may have occurred and healed in the 1–3 month follow up visits. This is not a groundbreaking study and there are some obvious flaws and unanswered questions, but it raises some important issues. Over the past 20+ years, the main focus of diabetic foot management has been on treating and preventing neuropathic foot ulcers. Neuropathy has been highlighted as the pivotal cause for foot ulceration and this has led to significant advances in foot ulcer management and research. Due to better care, improved services and improved longevity, neuropathic lesions are perhaps less frequent, whereas N/I are becoming more common. The tide is turning fast and we need to perhaps take a new look at our ulcer prevention care. I am not sure that this study is truly reflective of the norm, but we should take note nonetheless.
