Functional Walking Capacity as a Screening Indicator for Peripheral Arterial Disease in Patients with Type 2 Diabetes Mellitus: Development of a Clinical Risk Equation

Background/Objectives: Peripheral arterial disease (PAD) is a common complication in patients with type 2 diabetes mellitus (T2DM) and is associated with substantial morbidity. Standard diagnostic tools such as the ankle–brachial index (ABI) may be limited in certain clinical settings. Therefore, simple and practical approaches for identifying individuals at increased risk of PAD are needed. This study aimed to examine the association between functional walking capacity and PAD and to develop a simple clinical risk equation for identifying PAD risk in patients with T2DM. Methods: A cross-sectional analytical study was conducted in 223 patients with T2DM attending an outpatient clinic. PAD was diagnosed using ABI and toe–brachial index measurements. Functional walking capacity was assessed using the Incremental Shuttle Walk Test (ISWT). Multivariable logistic regression analysis was used to identify factors associated with PAD and to develop a risk equation. Model performance was evaluated using receiver operating characteristic (ROC) curve analysis. Results: An ISWT distance ≤ 215 m was independently associated with PAD (OR = 1.96, 95% CI 1.10–3.50, p = 0.022). The developed model demonstrated fair discriminative ability (AUC = 0.67). At a probability cutoff of 0.57, the model showed a sensitivity of 53.8% and a specificity of 76.4%. Conclusions: Reduced functional walking capacity was associated with PAD in patients with T2DM. The proposed equation demonstrated fair discriminatory ability and may provide preliminary information for PAD risk identification; however, further validation is required before clinical implementation.