Abstract
BACKGROUND: Fibromyalgia (FM) is a chronic widespread pain condition implicated in accelerated aging, functional decline, and physical frailty. OBJECTIVE: This study examined differences in performance-based and self-reported physical frailty phenotypes among middle-aged and older adults with and without FM. MATERIALS AND METHODS: A cross-sectional sample of 234 community-dwelling middle-aged and older adults with (59.0%) or without FM was analyzed. Physical frailty was defined as weakness, low physical activity, exhaustion, and slowness, assessed using validated performance-based (Fullerton Advanced Balance Scale [FAB], 8-foot up and go test [8FUPGT], 30-second chair stand [30SCS], 6-minute walk [6MWT], 30-foot walk [30FW]) and self-report measures (Rapid Assessment of Physical Activity [RAPA], fatigue numeric rating scale). Principal component analysis (PCA) evaluated the underlying structure of physical frailty indicators, yielding performance-based and self-reported components. Standardized factor scores were used as outcomes in regression analyses examining associations with pain intensity. RESULTS: PCA supported a two-component frailty structure explaining 61% of the variance. After adjusting for age, gender, depressive symptoms, and body mass index, greater pain intensity was associated with worse performance-based (B = -0.10, p < 0.001; adjusted R(2) = 0.36) and self-reported (B = -0.10, p < 0.001; adjusted R(2) = 0.39) frailty. DISCUSSION: Findings suggest that pain intensity is associated with frailty risk among aging adults, supporting the clinical utility of both performance-based and self-reported physical frailty assessments in FM.