Correlation of ankle brachial index with peripheral vascular disease in type 2 diabetes mellitus

Abstract

Purpose: The aim of this study was to correlate ankle brachial index (ABI) with peripheral vascular disease (PVD) in type 2 diabetes mellitus. Material and methods: This was a hospital based interdisciplinary prospective study. A total of 100 patients in the age group of 30 to 80 years having peripheral vascular disease with predefined inclusion criteria were included in the study. Patients with other causes of raised blood sugar or peripheral vascular disease were excluded by relevant investigations. Ankle Brachial Index (ABI) was calculated using sphygmomanometer, and Colour Doppler Ultrasound (CDU) was used to diagnose PVD. Both the ABI method and the CDU method were compared for detecting PVD. Results: In our study, mean age was 60.04 ± 5.03 years, mean body mass index was 27.10 ± 2.67 kg/m2 and mean duration of diabetes was 7.75 ± 1.50 years. Among the 68 diagnosed cases of PVD on CDU, 70.6% cases were detected to have PVD by the ABI method (true positive) whereas 20 (29.4%) cases remained undiagnosed when ABI alone was used for the diagnosis (false negative). Conversely, among 51 diagnosed cases of PVD by ABI method 5.9% cases were found to be normal on CDU (false positive). The ABI method was found to have specificity of 88.5% but the sensitivity was only 70.6%. Conclusion: ABI has a very high specificity but the sensitivity is low compared to colour Doppler ultrasound. Therefore, if ABI is abnormal, the diagnosis of PVD is almost certain but in symptomatic cases with normal ABI; colour Doppler should be performed to exclude the PVD.