Fatigue is independently associated with disease activity assessed using Physician Global Assessment (PGA), but not Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), according to study results published in RMD Open.
Differentiating disease activity and damage is essential in the treatment and long-term care of individuals with SLE. Researchers noted that fatigue may be related to SLE or sleep disorders, medications, or depression.
The study was aimed at determining the effect of fatigue on disease activity assessment using the PGA.
Researchers collected data on individuals from the Lupus BioBank of the Upper Rhein who fulfilled the 1997 American College of Rheumatology (ACR), SLEDAI, and PGA inclusion criteria.
Fatigue was measured using the Fatigue Scale for Motor and Cognitive Functions. Researchers considered fatigue scores as categorical rather than continuous data. The VMP V.13 software was used for data analysis, which included the Mann-Whitney test for continuous outcomes to compare independent groups In addition, the Chi-square test (or Fisher’s exact test when applicable) was used for quantitative data. To determine the variables that were independently associated with PGA (the dependent variable), univariate and multivariate linear regression models were used.
A total of 350 individuals with SLE were included in the analysis; the median age of participants was 42 years and 89% were women.
Overall, 257 (73%) participants reported significant fatigue. The median Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA)-SLEDAI score was 4. Fatigue was significantly associated with PGA (P =.004) but not SLEDAI (P =.43). Researchers noted that PGA was independently associated with severe fatigue (P =.03) and SLEDAI (P <.0001) in 2o multivariate models.
Based on study findings, the researchers suggested that fatigue is a confounding variable that could artificially increase PGA scores. They added that PGA is only reliable if it captures actual levels of disease activity.
According to the study authors, “Altogether, our findings highlight the importance of taking into account only objectively active…manifestations when assessing the PGA in SLE.”
Mertz P, Piga M, Chessa E, et al. Fatigue is independently associated with disease activity assessed using the Physician Global Assessment but not the SLEDAI in patients with systemic lupus erythematosus. RMD Open. Published online September 8, 2022. doi:10.1136/rmdopen-2022-002395