Differentiating obesity with and without prediabetes through skin findings: results from PREVIEW sub-study

Objective: To explore whether specific cutaneous findings are associated with prediabetes among adults with overweight or obesity, and may assist in clinical risk stratification. Materials and methods: This single-center, cross-sectional analysis included 191 adults with overweight or obesity (BMI ≥25 kg/m²) recruited during screening visits of the Bulgarian PREVIEW cohort; 151 participants had prediabetes, and 40 did not. A trained dermatologist performed a standardized skin examination. Xerosis, pruritus, and yellowish skin tone were assessed using 10-point visual scales. The prevalence of dermatological conditions was compared between groups, and exploratory binary logistic regression was used to examine associations with prediabetes. Results: Horseshoe-like plantar hyperkeratosis (HSLPH) was more frequent in participants with prediabetes than in those without (25.2% vs. 10.0%, p = 0.039). The presence of HSLPH was associated with higher odds of prediabetes (odds ratio 3.03, 95% confidence interval 1.01-9.06). HSLPH showed high specificity (90%) but low sensitivity (25%). The prevalence of other common skin conditions, including skin tags, onychomycosis, signs of chronic venous insufficiency, seborrheic dermatitis, and tinea pedis, did not differ between groups. Skin tag counts were not associated with body weight or BMI. No significant differences were observed in xerosis, pruritus, or yellowish skin tone scores. Conclusion: In adults with overweight or obesity, HSLPH was the only cutaneous finding associated with prediabetes and behaved as a specific but insensitive clinical sign. Its presence may serve as a visible clinical red flag prompting metabolic evaluation, whereas its absence does not exclude dysglycemia. Other common obesity-related skin findings were not discriminatory for prediabetes in this cohort.