The article titled “Dryness of Foot Skin Assessed by the Visual Indicator Test and Risk of Diabetic Foot Ulceration: A Prospective Observational Study” (Panagoulias et al., 2020) investigates the association between dryness of foot skin and the risk of developing diabetic foot ulcers (DFU) in individuals with diabetes mellitus (DM).
In a six-year, real-world prospective cohort study (2012–2017) involving 308 adults with diabetes (all free from foot ulcers or critical limb ischaemia at baseline), researchers investigated whether skin dryness—as measured by the visual indicator plaster method (IPM; Neuropad)—could predict the development of diabetic foot ulcers (DFUs). During the follow-up period, 55 participants (annual incidence ~2.97%) developed DFUs.
The study evaluated three modalities for neuropathy assessment: the Neuropathy Disability Score (NDS), vibration perception threshold (VPT), and Neuropad. After adjusting for age, sex, and diabetes duration, all three emerged as independent predictors of ulceration:
- Abnormal Neuropad conferred a hazard ratio (HR) of 3.32 (95% CI 1.46–7.55, p=0.004),
- High NDS (≥6), HR 2.78 (95% CI 1.55–5.01, p=0.001),
- Elevated VPT (≥25 V), HR 2.59 (95% CI 1.28–5.24, p=0.008).
Critically, Neuropad outperformed traditional measures in sensitivity for ulcer prediction (0.86 vs ~0.40 for NDS and VPT), though with lower specificity (0.49). Receiver-operating characteristic (ROC) analyses confirmed that all modalities could discriminate future ulceration (p < 0.001).
Why Neuropad stands out as a screening tool:
Neuropad is a non-invasive, simple, and rapid indicator plaster that detects sudomotor dysfunction by changing colour when sweat moisture is present. It is suitable for point-of-care use and even self-testing. Its high sensitivity makes it ideally suited for early detection of at-risk individuals—clinically prioritizing those who need preventive management before irreversible damage occurs.
This test aligns with growing evidence that sudomotor impairment is an early harbinger of diabetic foot pathology, preceding overt ulceration. By identifying subtle autonomic dysfunction, Neuropad adds depth to traditional neuropathy screening that focuses on large-fibre sensory loss.
Although its specificity is relatively low, meaning it may flag some false positives, this characteristic is not a drawback in screening contexts: missing a high-risk patient could result in ulceration and amputation, while further confirmatory tests can rule out low-risk cases.
Clinical implications:
Neuropad can be seamlessly integrated into routine diabetes care, whether in outpatient clinics or as a home-based self-test, enabling clinicians and patients to monitor sudomotor function easily and consistently.
Its introduction into screening protocols provides a sensitive, early-warning signal, triggering timely interventions, such as enhanced foot care education, glycemic optimization, or referral to podiatry, that could prevent ulcer development and its attendant morbidity.
In essence, this study powerfully demonstrates that Neuropad is a pragmatic, evidence-based game-changer in diabetic foot prevention. Its early detection capability, coupled with ease-of-use, positions Neuropad as a vital frontline instrument in reducing the burden of diabetic foot ulcers.