Validity of the Activities-specific Balance Confidence Scale in individuals with chronic obstructive pulmonary disease

Background Limited research assessed the validity of the Activities-specific Balance Confidence, ABC) Scale in individuals with chronic obstructive pulmonary disease, COPD) at risk of falls. We report on the scale's construct and criterion validity. Methods Construct validity was established by assessing known groups, convergent, and divergent validity. A receiver operating characteristic, (ROC) curve and logistic regression examined the criterion validity of the scale. Results In 223 individuals with COPD, the ABC Scale significantly, (p < 0.001) discriminated between groups, with lower scores for females [Mean difference (MD) = 10%], rollator use [MD = 13%], and fallers [MD = 12%], and had a strong association [r = 0.58, p < 0.001] with Berg Balance Scale. The scale distinguished fallers from non-fallers with a cutoff value of 58% [Area Under the Curve = 0.64, 95% CI = 0.57-0.72, p < 0.001] and significantly identified fall status [B, SE = -0.03, 0.01, p < 0.001] with an odds ratio of 0.97 [95%CI = 0.96-0.99]. The sensitivity, specificity, and test accuracy were: 61, 58, and 60%, respectively. Conclusion The ABC Scale showed evidence for known groups, convergent, and divergent validity and can assist in identifying fall status in individuals with COPD.