Friday, November 20, 2009

Fatigue a Good Indicator of RA Treatment Success

Newly reported research has demonstrated that a simple assessment of fatigue in patients with rheumatoid arthritis (RA) can be a reliable and sensitive measure of treatment success. Although, it does not necessarily replace other essential outcome assessments, such as pain and tender joint count.

Researchers at two medical centers in Ireland assessed 49 successive patients referred to their rheumatology clinics at baseline and 3 months after commencing TNF-blockade therapy for RA. Fatigue was measured using an 11-point numeric rating scale (0 to 10) and statistically compared with other core measures of therapeutic response. At baseline, the mean (+/- standard deviation) fatigue scores were 6.7 +/- 2.1 on the 11-point scale, and at 3 months these declined significantly to 4.3 +/- 2.6 (p < 0.001). Repeated testing showed that this simple approach for assessing fatigue was highly reliable. Overall, fatigue was ranked 3rd in terms of sensitivity to changes in therapeutic response as compared with a number of standard measurements of RA severity (in rank order): pain, tender joint count, fatigue, swollen joint count, health assessment questionnaire, C-Reactive Protein, and patient global health. However, compared with the other measures, fatigue accounted for the greatest share of independent variance; that is, it was a strong indicator of therapeutic response relatively uninfluenced by scores on other measures.

The researchers conclude that this simple and practical assessment of fatigue is reliable and sensitive to changes in response to therapy for RA; therefore, it should be routinely considered for inclusion as an outcome measure. However, this was an observational study in a relatively small sampling of patients, so further clinical experience in assessing fatigue as an important indicator of RA treatment response and success will help to establish its validity.

Reference: Minnock P, Kirwan J, Bresnihan B. Fatigue is a reliable, sensitive and unique outcome measure in rheumatoid arthritis. Rheumatology. 2009;48(12):1533-1536 [abstract here].