Consistency of Toe Systolic Pressures, Brachial Systolic Pressures, and Toe-Brachial Indices in People with and without Diabetes

Abstract

Background & aims: Toe Systolic Blood Pressures (TSPs) and Toe-Brachial Indices (TBIs) have been identified as useful adjuncts in the identification of pedal ischemia, peripheral artery occlusive diseases, and risk for either nonhealing of lower extremity wounds or for amputation. Valid measurement of TSPs and TBIs is therefore essential. However, it could be jeopardized by rater, instrument, and intratestee inconsistency. These three sources of inconsistency were examined in this research.

Methods: Five publications addressing TSP and TBI consistency were identified and their results were analyzed using intraclass correlation coefficients.

Results: Moderate variability in TSPs was found across all studies; greater variability was evidenced in brachial systolic pressure, particularly for people who had diabetes; and TBI values also exhibited considerable variability, but little difference between people who did and did not have diabetes.

Conclusion: These findings provide qualified evidence of consistency regarding measurement of TSPs but challenge TBI as a valid and useful indicator in screening, prognostic, and monitoring contexts, particularly for people who have diabetes. However, there is a prospect that TBI assessment could be improved by adherence to standardized protocols and by obtaining multiple measurements from toes and arms on a single occasion as well as on different occasions.

Keywords: Toe blood pressure; ankle-brachial index; blood pressure variability; brachial blood pressure; diabetes; intraclass correlation coefficient; rater reliability; toe-brachial index..