Contribution of abnormal BMI to adverse health-related quality of life outcomes after a 52-week therapy in patients with SLE

OBJECTIVES: To investigate whether abnormal BMI is associated with adverse health-related quality of life (HRQoL) outcome, including severe fatigue, after 52 weeks of standard therapy plus belimumab or placebo in patients with SLE. METHODS: We analysed data from the BLISS-52 (NCT00424476) and BLISS-76 (NCT00410384) trials (n = 1684). Adverse HRQoL was defined as SF-36 scores ≤ the fifth percentile in age- and sex-matched US population-based subjects, and FACIT-F scores <30. We compared BMI groups using the Pearson's χ2 test, and assessed independence with multivariable logistic regression analysis. RESULTS: Overweight (BMI ≥25 kg/m2) and obese (BMI ≥30 kg/m2) patients showed increased likelihood to exhibit adverse SF-36 physical component summary (OR: 1.8; 95% CI: 1.4, 2.3; P <0.001 and OR: 2.4; 95% CI: 1.8, 3.2; P <0.001, respectively) and FACIT-F (OR: 1.3; 95% CI: 1.1, 1.6; P = 0.010 and OR: 1.5; 95% CI: 1.2, 2.0; P = 0.002, respectively) scores at week 52. Underweight was associated with adverse SF-36 mental component summary scores, also after adjustment for sex, ancestry, age, disease duration, disease activity, organ damage and prednisone dose during the study period (OR: 2.1; 95% CI: 1.2, 3.6; P = 0.007). Addition of belimumab to standard therapy independently protected against adverse SF-36 general health (OR: 0.8; 95% CI: 0.6, 1.0; P = 0.025) and FACIT-F < 30 (OR: 0.8; 95% CI: 0.6, 1.0; P = 0.018). CONCLUSION: Overweight and obesity contributed to adverse physical and mental HRQoL outcomes after therapeutic intervention in SLE patients, and underweight contributed to adverse mental HRQoL outcome. A protective effect of belimumab against adverse general health and severe fatigue was implicated.