Accuracy of ankle-brachial index in screening for peripheral arterial disease in people with diabetes

Abstract

Although the ankle-brachial index (ABI) presents overall satisfactory accuracy, its sensitivity in the context of screening strategies does not ensure the detection of all individuals with peripheral arterial disease (PAD), especially in clinical situations where there is calcification of the arterial media layer. This study evaluated the accuracy of ABI in screening PAD among individuals with diabetes mellitus (DM) in a community setting. An observational study included only individuals with DM. ABI measurement was performed, and the lower limb duplex ultrasound (DU) was used as the reference standard for PAD diagnosis. Sensitivity, specificity, positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (LR+ and LR-) of ABI were assessed. The analysis included 194 limbs from 99 participants, with a PAD prevalence identified by DU of 15.98%. ABI demonstrated an accuracy of 87.63%, with a sensitivity of 35.48%, specificity of 97.55%, PPV of 73.33%, NPV of 89.83%, LR+ of 14.46, and LR- of 0.66. ABI showed high specificity but limited sensitivity in detecting PAD among individuals with DM in a community setting. An LR- of 0.66 suggests that a normal ABI result reduces but does not eliminate the possibility of PAD, highlighting the importance of complementary diagnostic approaches to enhance accuracy in identifying PAD in high-risk patients, such as those with DM. Incorporating additional diagnostic methods may be necessary to improve the effectiveness of PAD screening in this group.