The Activity Patterns Scale: An Analysis of its Construct Validity in Women with Fibromyalgia.

OBJECTIVES Avoidance, persistence and pacing are activity patterns which have different adaptive effects in chronic pain patients. Some inconsistent findings have been explained from a contextual perspective which underlines the purpose of the activity. In this way, avoidance, persistence and pacing are multidimensional constructs, nuanced by their goals. This multidimensionality has been supported with a new instrument, the Activity Patterns Scale, in heterogeneous chronic pain samples. Due to the clinical implications of this conceptualization, the complexity of the activity patterns and their relationships with health outcomes in fibromyalgia, our aim is to explore the construct validity of this scale in this pain problem, testing its internal structure and the relationships with other constructs. METHODS The sample included 702 women with diagnosis of fibromyalgia from tertiary (53.3%) and community settings (46.7%). Confirmatory Factor Analysis was conducted to test different factor structures of the activity patterns and Pearson correlation to explore the relationships with health outcomes and psychosocial variables. RESULTS A six factor structure showed acceptable fit indices (SRMR =0.062; RMSEA =0.066; CFI =0.908). Regarding health outcomes, the highest significant relationships was between activity avoidance and fibromyalgia impact (r =0.36) and excessive persistence and negative affect (r =0.41). DISCUSSION Avoidance and persistence activity patterns are shown as multidimensional constructs but not pacing. The ongoing pain in these women may make it difficult to regulate their activity taking into account other goals not contingent on pain fluctuations.