Diagnostic Accuracy of Stethoscope-Measured Ankle–Brachial Pressure Index for Early Detection of Peripheral Occlusive Vascular Disease in Asymptomatic Diabetic Patients: A Comparative Study with Doppler Ultrasonography

Abstract

Background: Peripheral occlusive vascular disease is a common yet underdiagnosed complication of diabetes mellitus and is associated with significant morbidity, including limb loss and cardiovascular events. Although Doppler ultrasonography is the standard diagnostic modality, its availability is limited in many primary healthcare settings. The ABPI (Ankle–Brachial Pressure Index) measured using a stethoscope may provide a simple, inexpensive, and accessible alternative for screening.

Methods: A cross-sectional diagnostic test evaluation was conducted among 106 diabetic patients without clinical features of (Peripheral Occlusive Vascular Disease) POVD attending a tertiary care center in Kerala. Stethoscope-measured ABPI served as the index test, while Doppler ultrasonography was used as the reference standard. ABPI values were compared with Doppler findings to determine sensitivity, specificity, PPV (Positive Predictive Value), NPV (Negative Predictive Value), diagnostic accuracy, and area under the receiver operating characteristic curve.

Results: The mean age of participants was 61.8 ± 10.5 years, with an almost equal gender distribution. Doppler ultrasonography identified POVD in 48.1% of patients. Doppler waveforms were triphasic in 51.9%, biphasic in 26.4%, and monophasic in 21.7% of participants. Stethoscope-measured ABPI demonstrated excellent diagnostic performance with an AUC of 0.879 (p<0.01). An optimal ABPI cut-off value of 0.94 yielded a sensitivity of 78.4%, specificity of 100%, PPV of 100%, NPV of 83.3%, and overall diagnostic accuracy of 89.6%. Longer duration of diabetes (p=0.005) and smoking (p=0.003) were significantly associated with POVD.

Conclusion: Nearly half of asymptomatic diabetic patients had subclinical POVD. Stethoscope-measured ABPI demonstrated high specificity and good overall diagnostic accuracy, making it a practical, cost-effective screening tool for early detection of POVD, particularly in resource-limited settings. Doppler confirmation is recommended for borderline or negative cases with high clinical suspicion.