Abstract EP45: Validation Of The Edinburgh Claudication Questionnaire For Identifying Peripheral Artery Diseasein Outpatient Cardiology Clinic: Single-center Experience

Abstract

Background: Peripheral artery disease (PAD) is prevalent in patients with chronic heart disease, and portends a worse cardiovascular outcome. Edinburgh Claudication Questionnaire (ECQ) is a commonly used screening tool aimed to identify PAD in general practice. Despite its common use, its accuracy had not been validated in a cardiac population in the USA. We aimed to evaluate the diagnostic accuracy of the ECQ as a means of identifying PAD in an outpatient cardiology clinic. Method: Subjects were recruited at outpatient cardiology clinic at Loma Linda University Medical Center between 2017 and 2019. Patients with previously diagnosed PAD were excluded. 119 patients completed ECQ during their routine clinic visit, and were subsequently referred for duplex ultrasound and Ankle-Brachial Index (ABI) measurement. ABI was used as a reference standard for the diagnosis of PAD. Result: rom a total of 119 patients, 53% were male with mean age was 68. Majority (87%) of patients had hypertension, and 16% were active smokers. There were 16% of patients who tested positive on the ECQ and 47% of them had positive ABI. In patients with a negative ECQ, 23% had a positive ABI result. Receiver operating characteristic curve analysis showed ECQ had sensitivity of 28% (95% CI 13.7-46.7), specificity of 89% (95% CI 79.8-94.3), PPV of 2.5% (95% CI 1.1-5.5) and NPV of 77.8% (0.7 to 1.0), which equates to a positive and negative likelihood ratio of 2.6 and 0.8 respectively. On subgroup analyses, the ECQ performed better among current smokers (AUC=0.64 95% CI 0.43 to 0.84) and among male patients (AUC=0.66 95% CI 0.53 to 0.78). In the subgroup of male patients who were currently smoking, the ECQ performed better with 50% sensitivity and 99% specificity (AUC=0.75 95% CI 0.56 to 0.94). Conclusion: The ECQ had good specificity but poor sensitivity in the cardiology outpatient setting making it a poor tool for screening on its own. Sensitivity was higher in male current smokers. Further study of its utilization in high-risk patients such as in male smokers may be of benefit.