Beyond Blood Pressure: Peripheral Artery Disease Diagnosis With the Ankle-Brachial Humidity Index

The ankle-brachial index (ABI) is the standard non-invasive diagnostic tool for peripheral artery disease, but it has some limitations, particularly in patients with arterial calcification. This study introduces the ankle-brachial humidity index as a novel diagnostic approach for peripheral artery disease.

In this prospective single-centre study in Turkey, 100 patients underwent comprehensive cardiovascular assessment including ABI measurements, lower extremity arterial Doppler ultrasonography, and skin moisture measurements using a digital moisture device. The ankle-brachial humidity index was calculated using standardised measurements taken at the wrist and foot under controlled conditions. Peripheral artery disease diagnosis was confirmed using standard criteria (ABI ≤0.90 or significant stenosis on Doppler ultrasound).

Of 100 patients, 33 were diagnosed with peripheral artery disease. Patients with peripheral artery disease showed significantly lower target leg humidity (median 14.3% vs 17.9%; p<0.001) and ankle-brachial humidity index values (median 0.75 vs 0.95; p<0.001) compared with patients without peripheral artery disease. The ankle-brachial humidity index emerged as an independent predictor of peripheral artery disease in logistic regression analysis (Odds ratio 0.598; 95% confidence interval 0.417-0.858; p=0.005). The ankle-brachial humidity index demonstrated significant correlations with established cardiovascular risk factors, including negative correlations with age (r=-0.235; p=0.001) and diabetes mellitus (r=-0.245; p<0.001).

The ankle-brachial humidity index represents a promising new diagnostic tool for peripheral artery disease that may complement existing methods, particularly in populations where traditional ABI measurements are less reliable.