In the era of life-prolonging
antiretroviral therapy, chronic fatigue is one of the most
prevalent and disabling
symptoms of people living with
HIV/AIDS, yet its measurement remains challenging. No instruments have been developed specifically to describe HIV-related fatigue. We assessed the reliability and
construct validity of the HIV-Related Fatigue Scale (HRFS), a 56-item self-report instrument developed through formative qualitative research and designed to measure the
intensity and consequences of fatigue as well as the circumstances surrounding fatigue in people living with
HIV. The HRFS has three main scales, which measure fatigue
intensity, the responsiveness of fatigue to circumstances and fatigue-related impairment of functioning. The functioning scale can be further divided into subscales measuring impairment of
activities of daily living, impairment of mental functioning and impairment of social functioning. Each scale demonstrated high
internal consistency (
Cronbach's alpha=0.93, 0.91 and 0.97 for the
intensity, responsiveness and functioning scales, respectively). The HRFS scales also demonstrated satisfactory
convergent validity when compared to other fatigue measures. HIV-Related Fatigue Scales were moderately
correlated with quality of nighttime
sleep (rho=0.46, 0.47 and 0.35) but showed only weak
correlations with daytime
sleepiness (rho=0.20, 0.33 and 0.18). The scales were also moderately
correlated with general mental and physical health as measured by the SF-36 Health Survey (rho ranged from 0.30 to 0.68 across the 8 SF-36 subscales with most >0.40). The HRFS is a promising tool to help facilitate research on the
prevalence,
etiology and consequences of fatigue in people living with
HIV.
