Diagnostic Value of Ankle-brachial Index in Peripheral Arterial Disease: a Meta-analysis

Background: In a previous review, we reported that ankle brachial index (ABI) ≤ 0.90 could reliably identify patients with peripheral artery disease (PAD). Since then, more studies have been published which may extend the power of a meta-analysis of studies of diagnostic accuracy of the ABI. MEDLINE and several other databases were searched for studies on sensitivity and specificity of using ABI ≤ 0.90 for PAD diagnosis compared with angiography.

Methods: Quality of each study was assessed by standards for reporting diagnostic accuracy initiative and quality assessment for studies of diagnostic accuracy tool. Heterogeneity was assessed using the Cochran Q statistic, χ(2), and inconsistency index. The area under the curve and Q* were estimated using summary receiver operator curve. The pooled diagnostic odds ratio (DOR), sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of ABI ≤ 0.90 to diagnose PAD were estimated using Meta-DiSc software (Meta-DiSc, Madrid, Spain).

Results: Four studies comprising 569 patients (922 limbs) met inclusion criteria. Significant heterogeneity among these studies was not detected in DOR but was evident in pooled sensitivity, specificity, PLR, and NLR. The area under the curve under the summary receiver operator curve is 0.87 (standard error = 0.02) and diagnostic accuracy (Q*) is 0.80 (standard error = 0.02). Additionally, DOR was 15.33 with corresponding 95% confidence intervals of 9.39-25.02. The pooled sensitivity and specificity of ABI ≤ 0.90 for PAD diagnosis were 75% and 86% and the pooled PLR and NLR were 4.18 and 0.29, respectively.

Conclusions: We conclude that test of ABI ≤ 0.90 can be a useful tool to identify PAD with serious stenosis in clinical practice.