Clinically significant fatigue in patients with systemic lupus erythematosus was associated with greater organ damage accrual and higher body mass index, but not with disease activity, researchers reported in BMJ Open.
In a cross-sectional cohort study, Marquis Chapman, of the National Institute of Arthritis and Musculoskeletal and Skin Diseases, and colleagues evaluated 183 patients with systemic lupus erythematosus seen during routine outpatient visits at a tertiary care center.
Fatigue was measured using the Fatigue Severity Scale (FSS), with scores of four or higher indicating clinically significant fatigue. Disease activity and damage were assessed using the Safety of Estrogens in Lupus Erythematosus: National Assessment Version of the Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI), respectively.
Among the cohort, 95 patients (52%) had clinically significant fatigue. Overall, patients had low disease activity, with a mean SELENA-SLEDAI score of three.
Compared with patients without fatigue (n = 88), those with fatigue had higher organ damage scores and higher body mass index. Mean SLICC/ACR DI scores were 1.9 vs 1.1, and mean body mass index was 30 vs 28. Disease activity scores were similar between groups.
In multivariable analyses, greater damage accrual and higher body mass index remained independently associated with fatigue. Disease activity, disease duration, hemoglobin level, and use of prednisone or hydroxychloroquine were not associated with fatigue.
The cohort was racially and ethnically diverse, with nearly 80% of patients from minority groups. Non-Hispanic White patients were more likely to report clinically significant fatigue than Black patients (71% vs 40%). In multivariable analyses, White race was also independently associated with fatigue, although the researchers noted that racial differences in fatigue reporting remain inconsistent across studies and warrant further investigation.
Analyses of individual damage domains showed statistically significant correlations between fatigue and pulmonary fibrosis, pulmonary hypertension, vascular tissue loss, neuropathy, diabetes, and osteoporosis. In stepwise models, neuropathy and pulmonary fibrosis remained independently associated with fatigue severity.
The findings are consistent with prior research suggesting that fatigue in systemic lupus erythematosus may be driven more by cumulative damage and comorbid factors than by current disease activity.
The study had several limitations, including its single-center, cross-sectional design, modest sample size, and reliance on patient-reported fatigue at a single time point. Most patients had low disease activity, and factors such as physical activity, pain, sleep, and psychosocial variables were not assessed.
“Organ damage accrual, specifically pulmonary fibrosis and neuropathy, and high BMI are associated with clinically significant fatigue in SLE,” the researchers wrote, noting that longitudinal and mechanistic studies are needed to better understand fatigue in this population.
Disclosures: The study was supported by the Intramural Research Program of the National Institutes of Health. The researchers reported no competing interests.
Source: BMJ Open
