Item selection and content validity of a multiple sclerosis fatigue short form using the PROMIS item bank.
|Title||Item selection and content validity of a multiple sclerosis fatigue short form using the PROMIS item bank.|
|Publication Type||Journal Article|
|Authors||Bamer AM, Cook KF, Roddey TS, Amtmann D|
|Journal||International Journal of MS Care|
Background: Research and clinical experience have indicated that fatigue is the most common symptom in individuals with multiple sclerosis (MS). Several fatigue scales have been used to measure fatigue, but modern psychometric analyses suggest that these scales have a number of shortcomings. Recently, the Patient Reported Outcomes Measurement Information Systems (PROMIS) network funded by the National Institutes of Health has developed a publicly available fatigue item bank. This study conducted preliminary work for a new fatigue short form extracted from this bank with content validity for measuring fatigue in this population. Methods: After item reduction for duplication, a subset of 44 of the 82 PROMIS fatigue items were evaluated by physicians (N = 8) who treat persons with MS. Physicians identified items they would select if they could ask only three questions of a person with MS about his or her fatigue. They then chose the item they would ask next if they could add a fourth item, and so on until they had selected their top ten items. Items rankings were scored and totaled. Results: Thirty-five items were chosen in the top ten by at least one physician. Of these, six items were chosen by at least half. The top-ranking item was “How often did your fatigue limit you at work (include work at home)?” Other high-ranking items asked about impact of fatigue on “finishing things,” physical function, thinking clearly, and social activities. Conclusions: The PROMIS item banking strategy allows construction of multiple short forms scored to the same metric, though additional work is needed to ensure content validity for specific clinical populations. This study demonstrates the usefulness of this method for ensuring content relevance and clinical validity of items for use in MS. A new MS-specific short form will be developed and validated using this study and follow-up studies with people living with MS.