Exploratory factor analysis
worry
SEPARATION
Factor loadings for the best-fitting EFA model solutions for symptoms, activity limitations, and emotions and lifestyle items are shown in Additional file Among the HRQOL items, the EFA results supported the separation of the 8 activity limitations items and the 13 emotions and lifestyle items in a 2-factor model (χ2[169, n = 103] = 229.00; P = 0.002; RMSEA = 0.06; CFI = 0.99, TLI = 0.98; SRMR = 0.06). Separate EFA models were estimated to further explore each of these two groups of items.For the activity limitations items, a 2-factor model comprising daily activities (4 items) and ambulation (4 items) subscales was the best-fitting solution (χ2[13, n = 103] = 16.37; P = 0.230; RMSEA = 0.05, CFI = 1.0, TLI = 1.0, SRMR = 0.02). However, the two factors were highly correlated (r = 0.85), indicating considerable overlap and potential support also for a single-factor solution.For the emotions and lifestyle items, a 2-factor model comprising emotional impact (4 items) and social impact (7 items) subscales was the best-fitting solution (χ2[53, n = 103] = 57.82; P = 0.302; RMSEA = 0.03; CFI = 1.0, TLI = 1.0; SRMR = 0.06). However, high correlations between the 2 factors (r = 0.71) again indicated potential support also for the 1-factor solution. The analysis further indicated relatively low factor loadings for one item (food restriction), and another item (worry to family) had significant loadings onto multiple scales.