Obesity linked to worse outcomes of pain, fatigue, depression in women with lupus
SAN DIEGO — Among women with systemic lupus erythematosus, obesity appears to be independently linked to worse patient-reported outcomes, suggesting that weight loss may improve outcomes for this population, according to findings presented at the American College of Rheumatology Annual Meeting.
“The research that I am presenting at this conference was inspired by previous work that showed that patients with lupus experienced big deferments in patient-reported outcomes, or PROs,” Sarah L. Patterson, MD, a fellow in rheumatology at the University of California, San Francisco, and an author of the study, said in her presentation.
“It's also been noted that these deferments in PROs are not fully explained by the severity of their lupus disease or by sociodemographic factors such as poverty. So, we therefore wanted to know whether body composition and, specifically, excess adipose tissue contributes to the worse health-related quality of life and greater symptom burden that we see in this particular patient population.”
In the study, Patterson and colleagues identified a sample of 148 patients with SLE (65% white, 14% Asian and 13% African-American; mean age, 48 ± 12.3 years) from the Arthritis Body Composition and Disability (ABCD) study. Eligible participants were women aged at least 18 years who had a diagnosis of SLE that could be corroborated by medical record review. The researchers calculated BMI and fat mass index (FMI). FMI measures total fat mass adjusted for height and was evaluated in the study using whole dual-energy X-ray absorptiometry. Obesity was defined using two designations: FMI of at least 13 kg/m2 and BMI of at least 30 kg/m2. The following four validated patient-reported outcomes were included as dependent variables: disease activity via Systemic Lupus Activity Questionnaire, depressive symptoms via Center for Epidemiologic Studies Depression Scale, pain assessed by SF-36 pain subscale and fatigue measured by SF-36 vitality subscale.
Multivariable linear regression was used to analyze correlations of obesity with patient-reported outcomes , adjusted for possible confounding factor (age, race, education, income, smoking status, disease duration, disease damage and prednisone use). Adjusted means for each outcome were then calculated based on the multivariable regression.
Of the patients in the sample, 17% had poverty-level income; 86% had education beyond high school; the mean duration of disease was 16 ± 9 years; and 45% were being treated with glucocorticoids.
Based on the FMI definition of obesity, 32% of patients met the criteria for obesity, whereas 30% were deemed obese by the BMI definition.
The multivariate regression model found that FMI-defined obesity was correlated with worse scores on each patient-reported outcome (greater disease activity, higher levels of depression, more pain and more fatigue). In the analyses that used the traditional BMI of at least 30 kg/m2 criteria, the same correlations were seen between obesity and each of the patient-reported outcomes.
“These findings have important clinical implications. The PROs that we measured, particularly pain and fatigue, are known to have profound effects on quality of life, and remain a major area of unmet need in people with lupus,” Patterson said. “In other words, there are many patients with lupus who are treated with aggressive immunomodulatory therapy and these symptoms of pain and fatigue persist. The relationship that we observed between excess fat and worse outcomes really underscores the need for lifestyle interventions for lupus patients who are overweight.” – by Jennifer Byrne
Patterson SL, et al. Abstract #2263. Presented at: American College of Rheumatology Annual Meeting; Nov. 4-8, 2017; San Diego.
Disclosures: The authors report no relevant financial disclosures.