Background/Purpose:

Obesity is associated with increased disease severity in multiple autoimmune conditions, likely via formation of pro-inflammatory adipokines [1]. However, the role of obesity in systemic lupus erythematosus (SLE) remains controversial. Studies have linked adiposity with a heightened risk of neurocognitive decline, renal impairment, and depressed quality of life — but not disease activity [1-2]. We aimed to reevaluate whether obesity independently associates with higher disease activity in SLE.

Methods:

Adult subjects with the diagnosis of SLE according to the Systemic Lupus International Collaborating Clinics criteria were recruited from the longitudinal, multi-ethnic, Southern California Lupus Registry (SCOLR). Sociodemographic and clinical variables were retrospectively collected. Obesity was defined as BMI >30kg/m² and participants were grouped accordingly. Disease activity was ascertained by calculating the SLE Disease Activity Index (SLEDAI). SLEDAI score of <5 and >5 were defined as low and high activity, respectively. Differences in sociodemographic and clinical variables were assessed using t-test and chi-square analyses. Finally, a multivariate regression model was utilized to determine the independent association between obesity and SLEDAI.

Results:

137 patients were included: 48 Caucasian (35%), 49 Hispanic (36%), 17 Asian (12%), and 23 African-American (17%). Mean age was 42.1± 15.4 years and 51 patients (37%) met criteria for obesity. Using univariate analysis (Table 1), increased BMI was significantly associated with SLEDAI (P = 0.023), but also sex (P = 0.040) and current steroid use (P = 0.019). Therefore, a multivariate regression model was utilized. After adjusting for age, sex, current steroid use, disease duration, and presence of nephritis, obesity remained independently associated with lupus activity (OR 1.051, P = 0.048) (Table 2).

Conclusion:

In contrast with prior studies, we observed an independent association between obesity and higher disease activity in SLE. This positive data, which is likely attributable to our more heterogeneous population compared to other studies, identifies obesity as a potential treatment target for improving SLE outcomes.

References:

[1] Versini M, Jeandel PY, Rosenthal E, Shoenfeld Y. Obesity in autoimmune diseases: not a passive bystander. Autoimmun Rev. 2014;13(9):981-1000.

[2] Rizk A, Gheita TA, Nassef S, Abdallah A. The impact of obesity in systemic lupus erythematosus on disease parameters, quality of life, functional capacity and the risk of atherosclerosis. Int J Rheum Dis. 2012;15(3):261-7.