RESEARCH - A comparison of fatigue correlates in RA and OA

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Rheumatology Advance Access published online on December 10, 2009

Rheumatology, doi:10.1093/rheumatology/kep367

A comparison of fatigue correlates in rheumatoid arthritis and

osteoarthritis: disparity in associations with disability, anxiety and

sleep disturbance

Simon Stebbings1, Herbison2, Terrence C. H. Doyle3, Gareth J.

Treharne4,5 and Highton1

1Department of Medicine, Dunedin School of Medicine, 2Department of

Preventive and Social Medicine, University of Otago, 3Department of

Radiology, Dunedin Hospital, Dunedin, 4Department of Psychology,

University of Otago, Otago, New Zealand and 5Department of

Rheumatology, Dudley Group of Hospitals NHS Foundation Trust, Dudley,

UK.

Abstract

Objectives. To investigate correlates of fatigue among individuals

with RA and OA, including mood, sleep, disease activity and

radiographic damage.

Methods. Fatigue was assessed using the Multidimensional Assessment of

Fatigue-Global Fatigue Index (MAF-GFI) in 103 patients with RA and 103

with OA. Sleep disturbance and pain were assessed using a visual

analogue scale anxiety and depression using the Hospital Anxiety and

Depression scale and disability using the HAQ. In the RA cohort, the

disease activity score-28 joint count (DAS-28) and the Van der Heijde

modified Sharp score were calculated, and in the OA cohort, the

Kellgren–Lawrence score and the WOMAC score calculated.

Results. The MAF-GFI scores were higher in the OA cohort (P = 0.02).

This was not significant after controlling for disability (P = 0.59).

OA participants reported greater pain, disability, depression and

sleeplessness than those with RA (all P < 0.01). The strongest

correlates of fatigue in the RA cohort were depression (P < 0.001) and

anxiety (P < 0.001). There was no significant association with pain (P

= 0.43), DAS-28 (P = 0.07), HAQ (P = 0.10) or Sharp score (P = 0.78).

In OA, the correlates of fatigue were older age (P = 0.02), sleep

disturbance (P = 0.03), depression (P = 0.04), disability (P = 0.04)

and lower CRP (P = 0.001).

Conclusions. Fatigue is common and severe in both RA and OA. In RA,

fatigue had no significant association with pain, disease activity,

disability or erosions, but was associated with depression and

anxiety. The disparity in correlates indicates that generalizing the

experience of fatigue between OA and RA is not appropriate. Fatigue is

an important domain in the assessment of disease impact.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/kep367v1?papetoc

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