Intratester and intertester reliability of toe pressure measurements in people with and without diabetes performed by podiatric physicians

Background: Toe pressures and the toe brachial index (TBI) represent possible screening tools for peripheral arterial disease; however, limited evidence is available regarding their reliability. The aim of this study was to determine intratester and intertester reliability of toe systolic pressure and the TBI in participants with and without diabetes performed by podiatric physicians. Methods: Two podiatric physicians performed toe and brachial pressure measurements on 80 participants, 40 with and 40 without diabetes, during two testing sessions using photoplethysmography and Doppler probe. Intraclass correlation coefficients (ICCs) and 95% limits of agreement were determined. Results: In people with diabetes, intratester reliability of toe pressure measurement was excellent for both testers (ICCs, 0.84 and 0.82). Reliability of the TBI was good (ICCs, 0.72 and 0.75) and brachial pressure fair (ICCs, 0.43 and 0.55). The intertester reliability of toe pressure (ICC, 0.82) and the TBI (ICC, 0.80) was excellent. Intertester reliability of brachial pressure was reduced in people with diabetes (ICC, 0.49). In age-matched participants, intratester reliability of toe pressure measurement was excellent for both testers (ICCs, 0.83 and 0.87), and reliability of the TBI (ICCs, 0.74 and 0.80) and brachial pressure (ICCs, 0.73 and 0.78) was good to excellent. Intertester reliability of toe pressure (ICC, 0.84), the TBI (ICC, 0.81), and brachial pressure (ICC, 0.77) was excellent. Conclusions: Toe pressures and the TBI demonstrated excellent reliability in people with and without diabetes and can be an effective component of lower-extremity vascular screening. However, wide limits of agreement relative to blood pressure values for both cohorts indicate that results should be interpreted with caution.