Assessment of the diagnostic accuracy of automated ankle brachial pressure index devices in patients with diagnosed or suspected peripheral arterial disease: protocol for a systematic review and meta-analysis

Background: The ankle brachial pressure index (ABPI) is a common diagnostic tool used in the assessment of peripheral arterial disease (PAD). The Doppler ultrasound technique is regarded as the gold-standard method for ABPI measurement; however, time constraints and operator experience limit widespread application in clinical practice, particularly in a primary care setting. Automated ABPI devices are not currently widely used due to a lack of evidence regarding their diagnostic accuracy. The aim of this proposed systematic review and meta-analysis is to explore the current evidence for the accuracy of automated ABPI devices in people with known or suspected PAD. Methods: Systematic searches of electronic databases and grey literature will be performed. We plan to include studies of adult patients with diagnosed or suspected PAD that have compared automated ABPI device readings with manual Doppler ABPI measurements or confirmed the diagnosis of PAD using vascular imaging. Two independent reviewers will screen identified literature for inclusion and perform data extraction. Extracted data will include study and participant characteristics, a description of the index and reference tests, outcome measures and main findings. The methodological quality of selected studies will be assessed using QUADAS-2 and QUADAS-C. Meta-analysis will be performed for studies with paired designs using a bivariate random-effect model to provide pooled estimates of summary accuracy statistics. We intend to conduct subgroup analyses and meta-regression for suspected sources of heterogeneity. Discussion: This review aims to assess the diagnostic accuracy of automated ABPI devices for detecting PAD in patients with known or suspected PAD compared with manual Doppler ABPI measurements or vascular imaging. These results will be used to inform clinical practice and guide future trials.