Measurement of fatigue in HIV-positive adults: reliability and validity of the Global Fatigue Index.

Fatigue is among the most common and distressing symptoms in patients with HIV/AIDS. Little is known about the clinical assessment of fatigue, especially in patients using highly active antiretroviral regimens. The purpose of this study was to evaluate the psychometric properties of the Global Fatigue Index (GFI) in a community-based sample of 209 patients with HIV/AIDS. The GFI is a measure that quantifies five dimensions of fatigue from the Multidimensional Assessment of Fatigue instrument into one score. To assess construct validity, the study included measures of depression, perceived stress, activities of daily living (ADLs), health behaviors, and clinical markers. Cronbach's alpha was calculated for internal consistency reliability, and factor analysis and bivariate correlations were conducted. The GFI was found to be easily self-administered, reliable, and a valid measure of overall fatigue burden in an HIV population. This instrument may be used by clinicians and researchers for assessing fatigue.