A comparison of two methods of measuring fatigue in patients on chronic haemodialysis: visual analogue vs Likert scale.

The study compared level of fatigue measured by two self-report instruments in 43 patients on chronic haemodialysis. The two fatigue measures were the multi-item fatigue subscale of the Profile of Mood States (POMS) and a single-item visual analogue scale (VAS). There was a significant relationship between the two measures (r = 0.80); however, the shared variance was only 64%. Males and females, as well as subjects of different ages, responded to the two scales in different ways. Nurses need to know that different tools may give different results, even when the same concept, that is fatigue, is being measured in the same subjects at the same time.