Obesity is associated with pain and impaired mobility despite therapy in systemic lupus erythematosus

Objective: To investigate whether abnormal BMI is associated with health-related quality of life (HRQoL) impairments, defined as patient-reported problems within the different dimensions of the three-level EQ-5D (EQ-5D-3L), before and after treatment for active systemic lupus erythematosus (SLE). Patients and methods: We conducted a post-hoc analysis of data from two phase III clinical trials of belimumab in SLE, i.e., BLISS-52 (n = 865) and BLISS-76 (n = 819). Underweight was defined as BMI <18.5 kg/m(2), normal weight as BMI >= 18.5 but <25 kg/m(2), pre-obesity as BMI >= 25 but <30 kg/m(2), and obesity as BMI >= 30 kg/m(2). We investigated associations between BMI groups and problems (level 2 or 3) within each one of the five EQ-5D dimensions before treatment initiation and at week 52, using logistic regression analysis adjusting for age, ethnicity, disease activity, and glucocorticoid dose, and for the post-treatment analysis also for belimumab treatment and baseline EQ-5D-3L responses. Results: Of 1,684 patients included, 73 (4%) were classified as underweight, 850 (50%) as normal weight, 438 (26%) as pre-obese, and 323 (19%) as obese. At baseline, obesity was associated with mild to severe problems in all EQ-5D dimensions (p < 0.05 for all), yielding the strongest association with problems in mobility (adjusted odds ratio, aOR: 2.1; 95% confidence interval, CI: 1.6-2.8; p < 0.001). Pre-obesity was also associated with problems in mobility (aOR: 1.4; 95% CI: 1.1-1.8; p = 0.005). Post-intervention, obesity was associated with problems in mobility and pain/discomfort, and pre-obesity with problems in mobility and self-care (p < 0.05 for all). Conclusion: Our study adds to the evidence that high BMI negatively affects SLE patients' HRQoL, with obesity being associated with pain and impaired mobility despite therapy.