Are estimates of meaningful decline in mobility performance consistent among clinically important subgroups? (Health ABC Study).

Background: Meaningful change criteria help determine if function has improved or declined, but their magnitudes may vary across clinically relevant subgroups. We estimate meaningful decline in four common measures of physical performance in subgroups of older adults based on initial performance, demographics, chronic conditions, and health status. Methods: We used baseline (Year 1) and Year 4 data from the Health, Aging and Body Composition (Health ABC) study, a well-functioning cohort at baseline of white and black men and women (age 70-79), to evaluate the magnitude of meaningful decline in performance (6 m gait speed, 400-m walk time (400MWT), Short Physical Performance Battery, and Health ABC Physical Performance Battery (PPB), based on self-reported perceived mobility anchors (climbing 10 steps and walking = mile). Estimates were stratified by initial performance, demographics, health status, chronic conditions, and body mass index, and compared across strata. Results: For all four measures, small and substantial decline estimates were generally consistent among subgroups based on initial performance, demographics, health status, and chronic conditions. The only exception was for 400MWT, where men had greater estimates than women. For PPB, small change was 0.12 points, and substantial change was 0.22 points. Conclusions: Estimates of small and substantial meaningful decline resemble those previously reported for gait speed, 400MWT, and SPPB. Magnitudes of meaningful performance decline appear to be generally consistent across strata of initial performance, demographics, health status, body mass index, and chronic conditions.