Development and Validation of The Activity-Based Checks (ABCs) of Pain: A Functional Pain Scale.

The Activity-Based-Checks of Pain (ABCs) is a pain assessment tool incorporating activities of daily living and instrumental activities of daily living. Unlike widely used pain scales which are oftentimes unidimensional and highly subjective, the ABCs was designed to focus on function capabilities and limitations of patients due to pain. This study sought out to validate the factorial structure of the ABCs and assess its use in participants with chronic pain. Participants were recruited in two phases from Prolific - an online service designed to identify research participant recruitment based on study criteria. Phase one optimized the design of the ABCs, with 297 subjects selecting their preferred icon for each function and rating its understandability. The most preferred and understandable icons were then used in phase two, where 304 chronic pain participants completed the ABCs, PROMIS-29, additional PROMIS items that were analogous to the ABCs functions but not represented in the PROMIS-29, and the Brief Pain Inventory (BPI). Data was analyzed using exploratory factor analysis and confirmatory factor analysis demonstrating four factor loadings: multi-planal activities, sitting/hip flexor pain, walking/ambulation, and pain interference with lightweight unilateral activities. High internal consistency was demonstrated with all four factor loadings. Correlations between items in the ABCs, PROMIS, and BPI resulted in moderate to strong correlations demonstrating strong evidence for the validity of the ABCs as a functional pain assessment tool.