Development of a physical performance summary score in middle age: Findings from the CARDIA Function study

Few physical performance batteries exist that appropriately evaluate physical limitations in middle-aged adults. We aimed to develop a physical performance summary score that is appropriate for use in epidemiology studies of middle-aged adults using data from the Coronary Artery Risk Development in Young Adults (CARDIA) Function study, which assessed self-reported function (PROMIS-SF20a) and physical performance measures (gait speed, balance, lower-body strength, grip strength, and cardiovascular endurance). The CARDIA Physical Performance (CAPP) score was developed using sex-specific quartiles, assigning points based on these quartiles (0 for not attempted, 1-4 for each quartile), and summing points across all performance measures (0-20, higher scores reflect greater performance). We also examined the relationship between CAPP score and other function-related measures (physical activity, quality of life, sedentary behavior, body mass index, and waist circumference). Among 2,021 CARDIA Function participants [mean age: 60.0±3.6 years; 58% female; 44% Black] a 1-point higher CAPP score (μ= 12.3±4.1) was associated with a 0.85 higher PROMIS-SF20a score (β= 0.85, p< 0.001). CAPP score had a canonical correlation coefficient of 0.63 (p< 0.0001) suggesting a strong correlation with other function-related measures. CAPP score captured a wide range of physical performance and was correlated with self-reported function and other function-related measures.