Cachexia developed in 56% of adults with systemic lupus erythematosus over a 5-year period, and 18% did not recover their weight, based on data from more than 2,000 patients.
Sara Freeman/MDedge News
Dr. George Stojan
Although weight loss is common in patients with systemic lupus erythematosus (SLE), cachexia, a disorder of involuntary weight loss, is largely undescribed in SLE patients, wrote George Stojan, MD, of Johns Hopkins University, Baltimore, and colleagues. Cachexia has been described in a range of disorders, including heart failure, renal disease, and rheumatoid arthritis, they said. “Cachexia has been shown to lead to progressive functional impairment, treatment-related complications, poor quality of life, and increased mortality,” they added.
In a study published in Arthritis Care & Research, the investigators reviewed data from the Hopkins Lupus Cohort, consisting of all SLE patients seen at a single center who are followed at least quarterly.
The study population included 2,452 SLE patients older than 18 years who had their weight assessed at each clinic visit. The average follow-up period was 7.75 years, and the average number of weight measurements per patient was nearly 24.
Cachexia was defined as a 5% stable weight loss in 6 months without starvation relative to the average weight in all prior cohort visits; and/or weight loss of more than 2% without starvation relative to the average weight in all prior cohort visits in addition to a body mass index less than 20 kg/m2.
Overall, the risk for cachexia within 5 years of entering the study was significantly higher in patients with a BMI less than 20, current steroid use, vasculitis, lupus nephritis, serositis, hematologic lupus, positive anti-double strand DNA (anti-dsDNA), anti-Smith (anti-Sm), and antiribonucleoprotein (anti-RNP), the researchers noted. After adjustment for prednisone use, cachexia remained significantly associated with lupus nephritis, vasculitis, serositis, and hematologic lupus.
Future organ damage including cataracts, retinal change or optic atrophy, cognitive impairment, cerebrovascular accidents, cranial or peripheral neuropathy, pulmonary hypertension, pleural fibrosis, angina or coronary bypass, bowel infarction or resection, osteoporosis, avascular necrosis, and premature gonadal failure were significantly more likely among patients with intermittent cachexia, compared with those with continuous or no cachexia. Patients with continuous cachexia were significantly more likely to experience an estimated glomerular filtration rate less than 50 mL/min/1.73 m2, proteinuria greater than 3.5 g/day, and end-stage renal disease.
The patients who never developed cachexia were significantly less likely to develop malignancies, diabetes, valvular disease, or cardiomyopathy than were those who did have cachexia, the researchers said.
The mechanisms of action for cachexia in SLE remain unclear, but studies in cancer patients may provide some guidance, the researchers noted. “Tumors secrete a range of procachexia factors thought to be unique to cancer-related cachexia, and colloquially termed the ‘tumor secretome,’ ” they said. “Every single proinflammatory cytokine mentioned as part of the tumor secretome has a role in lupus pathogenesis,” suggesting a possible common pathway to cachexia across different diseases, they said.
The study findings were limited by several factors, mainly the use of BMI to measure weight “since BMI is a rather poor indicator of percent of body fat,” the researchers noted. “Ideally, cachexia would be defined as sarcopenia based on body composition evaluation with a dual x-ray absorptiometry,” they wrote.
The study was supported by the National Institutes of Health and the NIH Roadmap for Medical Research. The researchers had no financial conflicts to disclose.
SOURCE: Stojan G et al. Arthritis Care Res. 2020 Aug 2. doi: 10.1002/acr.24395.