Abstract
Purpose: To examine the psychometric properties of the 9-item Fatigue Severity Scale (FSS) using a Rasch model application. Methods: A convenience sample of HIV-infected adults was recruited, and a subset of the sample was assessed at 6-month intervals for 2 years. Socio-demographic, clinical, and symptom data were collected by self-report questionnaires. CD4 T-cell count and viral load measures were obtained from medical records. The Rasch analysis included 316 participants with 698 valid questionnaires. Results: FSS item 2 did not advanced monotonically, and items 1 and 2 did not show acceptable goodness-of-fit to the Rasch model. A reduced FSS 7-item version demonstrated acceptable goodness-of-fit and explained 61.2% of the total variance in the scale. In the FSS-7 item version, no uniform Differential Item Functioning was found in relation to time of evaluation or to any of the socio-demographic or clinical variables. Conclusion This study demonstrated that the FSS-7 has better psychometric properties than the FSS-9 in this HIV sample and that responses to the different items are comparable over time and unrelated to socio-demographic and clinical variables.
Original language | English (US) |
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Pages (from-to) | 1447-1456 |
Number of pages | 10 |
Journal | Quality of Life Research |
Volume | 20 |
Issue number | 9 |
DOIs | |
State | Published - Nov 2011 |
Keywords
- Fatigue
- HIV
- Psychometrics
- Quality of life
- Symptoms
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health