Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Measuring Fatigue in Patients with Inflammatory Arthritis in Clinical Practice: Single Dimension and Multidimensional Scale Comparison.

Minnock,  Patricia, Bresnihan,  Barry, Gabrielle,  McKee, FitzGerald,  Oliver, Veale,  Douglas

Rheumatology Rehabilitation, Our Lady's Hospice and Care Services, Dublin, Ireland
St Vincent's University Hospital, Dublin, Ireland
Trinity College Dublin, Dublin, Ireland

Background:

The ease of use of a measurement instrument frequently determines instrument choice and is an important consideration for outcome assessment in routine clinical practice. The aim of this study was to compare the measurement properties of one-dimensional and multidimensional fatigue scales in patients with inflammatory arthritis.

Methods:

Patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) commencing anti-TNF therapy were clinically evaluated using the 6-core outcome measures, and fatigue at baseline, 3-months and 6-months. Fatigue was measured using 2 fatigue scales validated for use in RA 1) a one dimensional 5 point ordinal scale (OS), and 2) a multidimensional assessment of fatigue scales (MAF). Fatigue levels were quantified and the properties of a one-dimensional scale versus a multidimensional fatigue scale were evaluated.

Results:

One-hundred thirty patients were evaluated (RA, 90; PsA, 40). Mean age (SD) years, and disease duration at inclusion were 52 (13), 12 (11), respectively. Mean (SD) MAF levels (range 1–50) were 27.5 (11.1) at baseline, 18.07 (12.1) at 3-months, and 19.04 (11.8) at 6-months and demonstrated statistical difference (ANOVA p<=0.001). Change in fatigue captured by the OS were statistically significant at both 3–months and 6-months c2 (2) = 31.5; p= 0.000 (Friedman test). MAF and OS scores demonstrated strong and significant correlations at the 3 time points, r=0.587; r=0.689, and r=0.686 (p<=0.000), respectively, (Kendall's tau_b). Fatigue scores corresponded as follows

Fatigue ScoresNoneMildModerateSevereVery Severe
Baseline     
5-point ordinal scale (%)10 (8)19 (15)47 (38)41 (33)7 (6)
MAF Mean (SD) (Range 1–50)8.7 (8.4)18. (8.2)27 (8.1)35 (7.1)40 (5.1)
3-months     
5-point ordinal scale (%)17 (16)40 (37)41 (38)11 (10) 
MAF Mean (SD) (Range 1–50)6 (11.9)10 (10.2)19 (10)24 (11)21 (11)
6-months     
5-point ordinal scale (%)12 (14)33 (39)29 (34)9 (11)1 (1.2)
MAF Mean (SD) (Range 1–50)6.7 (6.1)11 (11)19 (10)26 (11)24 (7)

MAF scores moderately correlated with Pain 0.423 (0.578), (0.482); GH 0.425 (0.578), (0.500) and HAQ 0.470 (0.345), (0.344) (p<=0.001) at baseline, at 3-months, and at 6-months, respectively. Similarly, OS scores correlated with Pain 0.489 (0.495), (0.456); GH 0.532 (0.536), (0.515) and HAQ 0.407; (0.346), (0.347) (p= 0.001) at baseline, at 3-months, and at 6-months, respectively. The correlations between fatigue and the core outcome measures were equivalent at all time points regardless of the scale employed. Using the standardised response mean (SRM), sensitivity to change of MAF was moderate (0.78) at 3-months and large (0.66) at 6-months. Fatigue ranked third at 3-months, next to TJC and SJC, and sixth at 6-months relative to the other measures. Noteworthy was the observation that fatigue was ranked higher than CRP at 6-months.

Conclusion:

These finding support the use of a single-item ordinal fatigue scale, in the quantification of this multi-dimensional patient reported symptom, in busy routine clinical practice.

To cite this abstract, please use the following information:
Minnock, Patricia, Bresnihan, Barry, Gabrielle, McKee, FitzGerald, Oliver, Veale, Douglas; Measuring Fatigue in Patients with Inflammatory Arthritis in Clinical Practice: Single Dimension and Multidimensional Scale Comparison. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2065
DOI: 10.1002/art.29830

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