Confirmatory factor analysis of the Patient reported Outcomes Measurement Information System (PROMIS) adult domain framework using item response theory scores

Background: To guide measure development, National Institutes of Health-supported Patient reported Outcomes Measurement Information System (PROMIS) investigators developed a hierarchical domain framework. The framework specifies health domains at multiple levels. The initial PROMIS domain framework specified that physical function and symptoms such as Pain and Fatigue indicate Physical Health (PH); Depression, Anxiety, and Anger indicate Mental Health (MH); and Social Role Performance and Social Satisfaction indicate Social Health (SH). We used confirmatory factor analyses to evaluate the fit of the hypothesized framework to data collected from a large sample. Methods: We used data (n = 14,098) from PROMIS's wave 1 field test and estimated domain scores using the PROMIS item response theory parameters. We then used confirmatory factor analyses to test whether the domains corresponded to the PROMIS domain framework as expected. Results: A model corresponding to the domain framework did not provide ideal fit [root mean square error of approximation (RMSEA) = 0.13; comparative fit index (CFI) = 0.92; Tucker Lewis Index (TLI) = 0.88; standardized root mean square residual (SRMR) = 0.09]. On the basis of modification indices and exploratory factor analyses, we allowed Fatigue to load on both PH and MH. This model fit the data acceptably (RMSEA = 0.08; CFI = 0.97; TLI = 0.96; SRMR= 0.03). Discussion: Our findings generally support the PROMIS domain framework. Allowing Fatigue to load on both PH and MH improved fit considerably.