Screening the Diabetic Foot: How Clinicians Detect Loss of Protective Sensation and Peripheral Artery Disease Before an Ulcer Forms
Diabetes-related foot disease remains one of the most common and costly complications of diabetes, yet a large share of it is preventable. A systematic review and meta-analysis of global data estimated the worldwide prevalence of diabetic foot ulceration at 6.3%, with North America reporting the highest regional rate at roughly 13%. Because most ulcers develop on a foot that has quietly lost its ability to feel injury, the single most valuable step in prevention is identifying the at-risk foot before skin breaks down. This article reviews how loss of protective sensation and peripheral artery disease are screened for, and how those findings drive risk stratification.
Why Early Detection Matters
The foot at risk is common. In a cross-sectional study of outpatients with diabetes applying the International Working Group on the Diabetic Foot (IWGDF) 2019 criteria, 54.3% of patients met the definition of a foot at risk, with peripheral neuropathy present in 37.3% and peripheral artery disease in 30.1%. Risk rose with longer diabetes duration, older age, and painful neuropathic symptoms. These figures underscore a clinical reality: a substantial proportion of people with diabetes have measurable nerve or vascular changes long before they notice a problem, which is precisely why structured screening rather than symptom-based detection is recommended.
Screening for Loss of Protective Sensation
Loss of protective sensation (LOPS) is the neuropathic loss of the ability to perceive potentially damaging pressure, friction, or trauma. The IWGDF guidelines recommend screening every person with diabetes at very low risk at least annually for LOPS and peripheral artery disease, and screening those at higher risk more frequently for additional risk factors.
The reference test for LOPS is the Semmes-Weinstein 10-gram monofilament, applied to several plantar sites; inability to feel the filament at one or more sites indicates LOPS. Where a monofilament is unavailable, the Ipswich Touch Test—lightly touching the tips of specific toes—offers a simple bedside alternative. A diagnostic-accuracy study comparing the Ipswich Touch Test against the 10-gram monofilament reported a specificity of 98.6% and an area under the curve of 0.85, but a sensitivity of only 70.8%, meaning it is useful for confirming LOPS yet may miss some cases and should be applied with caution as a sole screening tool. Vibration perception, typically with a 128-Hz tuning fork, is a common complementary bedside test.
Screening for Peripheral Artery Disease
Peripheral artery disease (PAD) compounds neuropathic risk by impairing the blood supply needed for wound healing. Screening begins with a history and palpation of the foot pulses. Because pulses can be unreliable, IWGDF guidance supports objective vascular assessment—such as ankle-brachial index, toe-brachial index, or Doppler waveform analysis—when PAD is suspected. Identifying PAD is important not only for ulcer risk but because its presence changes management thresholds, referral urgency, and healing expectations for any wound that does occur.
Turning Findings into a Risk Category
Screening results are combined into a risk stratification that guides how often the foot should be examined and what preventive care is offered. The IWGDF system ranges from very low risk (no LOPS and no PAD) up to the highest category, which combines LOPS or PAD with a history of foot ulcer, amputation, or end-stage renal disease. The 2023 IWGDF prevention guideline recommends that once someone is identified as at risk, care shifts to structured self-care education, instruction never to walk without suitable foot protection, treatment of any pre-ulcerative lesion, and, for those at moderate-to-high risk, properly fitting therapeutic footwear with a demonstrated plantar-pressure-relieving effect. Monitoring foot skin temperature at home is described as an adjunct that may help flag inflammation before an ulcer becomes visible. Integrated, multidisciplinary foot care is recommended for those at highest risk to reduce recurrence.
Key Takeaways
Diabetic foot ulceration is common worldwide, and the foot at risk frequently exists without symptoms. Annual screening for loss of protective sensation—using the 10-gram monofilament, supplemented where needed by the Ipswich Touch Test and vibration testing—together with assessment for peripheral artery disease, allows clinicians to assign a risk category and match the intensity of preventive care to that risk. Detecting these silent changes early is the foundation on which every downstream prevention strategy, from education to therapeutic footwear, is built.
References
Bus SA, Sacco ICN, Monteiro-Soares M, et al. Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2023;40(3):e3651.
Bus SA, Lavery LA, Monteiro-Soares M, et al. Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2019 update). Diabetes/Metabolism Research and Reviews. 2020;36(S1):e3269.
Zhang P, Lu J, Jing Y, Tang S, Zhu D, Bi Y. Global epidemiology of diabetic foot ulceration: a systematic review and meta-analysis. Annals of Medicine. 2017;49(2):106–116.
Yovera-Aldana M, Pérez-Cavero S, Pinedo-Torres I, Zubiate-López C. Prevalence of Foot At-Risk and its Associated Characteristics among Outpatients with Diabetes Mellitus in a Peruvian Public Hospital. The Review of Diabetic Studies. 2022;18(1):1–9.
Khumchum N, Koonalinthip N, Janchai S. Accuracy and reliability of the Ipswich touch test in identifying loss of protective sensation among diabetic patients. The Foot. 2024;61:102132.
Comments
