Letters to the Editor
Additional components to measuring fatigue in patients with systemic lupus erythematosus: Comment on the article by the Ad Hoc Committee on systemic lupus erythematosus response criteria for fatigue
Article first published online: 24 JUN 2008
Copyright © 2008 by the American College of Rheumatology
Arthritis Care & Research
Volume 59, Issue 7, page 1049, 15 July 2008
How to Cite
Wallace, D. J. (2008), Additional components to measuring fatigue in patients with systemic lupus erythematosus: Comment on the article by the Ad Hoc Committee on systemic lupus erythematosus response criteria for fatigue. Arthritis & Rheumatism, 59: 1049. doi: 10.1002/art.23832
- Issue published online: 24 JUN 2008
- Article first published online: 24 JUN 2008
To the Editors:
At a recent lupus symposium, I asked the 200 patients in attendance how many had significant fatigue. So many hands went up that I followed this up with, “How many are not generally tired?” to which a handful responded. The impact of fatigue has a major influence on the quality of life of patients with lupus (1).
In a recent article published in Arthritis Care & Research, an ad hoc committee performed a systematic review of 34 studies and 15 fatigue instruments and concluded that the Fatigue Severity Scale (FSS) was the best of many flawed instruments for lupus, and a 15% decrease in the FSS represented an important improvement or response (2). Five comorbidities (disease activity, depression, pain, sleep, and anemia) were reviewed in Table 4 in the article and were found to be potential confounding factors to any metric.
Unfortunately, the committee failed to consider or recommend several additional components to the fatigue equation. Concomitant medications were not mentioned in the article. Corticosteroids, antihypertensives, antidepressants, and analgesic medications, for example, influence symptoms of fatigue, and most lupus patients take 1 or more of these agents. Hypothyroidism was also not mentioned. Twenty percent of patients with systemic lupus erythematosus (SLE) have thyroid autoantibodies and up to 10% of patients with lupus take thyroid medication. Diabetes/insulin resistance was not included in the article. Up to 50% of all lupus patients take corticosteroids that commonly produce glycemic changes, which influence energy levels.
Most patients with active SLE are young women. At any given moment, anxiety, malnutrition (especially in patients who are anorexic or on special diets), iron deficiency anemia due to heavy menstrual periods (as opposed to anemia from SLE), or use of recreational medications can influence complaints of fatigue. Hormonal imbalance was not mentioned; neither was aerobic conditioning nor exercise.
Fibromyalgia was not considered in the Materials and Methods or Results sections or Table 4 in the article, and it was not part of any of the 15 instruments. It was mentioned in one sentence in the Discussion section. Because up to 30% of patients with SLE have fibromyalgia and 85% of these individuals have prominent complaints of fatigue, this passing mention without elaboration was unfortunate.
Damage due to scarring rather than disease activity was not considered. For example, renal insufficiency or the need for dialysis due to scarring rather than disease activity is present in 10% of patients with SLE and is associated with fatigue. This also applies to pulmonary fibrosis. Adjustments for an elevated Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index (3) should be made in fatigue evaluations.
To summarize, fatigue is a pervasive feature of SLE that deserves more rigorous study. A 15% change in the FSS is insignificant unless all of the above factors are considered, in order to ascertain if fatigue is truly due to lupus or not. A lupus-specific fatigue index needs to be formulated. I believe the committee provided a disservice to the lupus community with recommendations that have little basis in reality and will not further advance the design of future clinical trials.
- 1Managing fatigue in patients with SLE. J Musculoskelet Med 2001; 18: 149–52., .
Daniel J. Wallace MD*, * Cedars-Sinai Medical Center, Los Angeles, CA.