SLICC-Frailty Index and Its Association with Low Bone Mineral Density and Vertebral Fractures in Women with Systemic Lupus Erythematosus

The Systemic Lupus International Clinics (SLICC)-Frailty Index (FI) is associated with adverse outcomes in systemic lupus erythematosus (SLE). However, to our knowledge, its association with bone mineral density (BMD) and vertebral fractures (VF), has not been investigated using a standardized methods. Our aim was to evaluate the relationship between frailty assessed by SLICC-FI, and BMD and VF in Mestizo women with SLE. Adult women were included in this cross-sectional study. Information concerning the risk factors for VF and BMD in the lumbar spine and total hip was acquired. SLICC-FI was assessed at baseline. A semi-quantitative method was utilized to evaluate the prevalence of VF on lateral thoracolumbar radiographs. Univariate and multivariate regression analyses were performed adjusting for age, body mass index (BMI), SLE duration, cumulative glucocorticoid dose, bisphosphonate use, and BMD measurements. We included 202 women with SLE (mean age [SD] = 43.3 [13.6] years). The mean (SD) SLICC-FI value was 0.14 (0.09). Eleven (5.4%) patients were categorized as robust, 62 (30.7%) as relatively less fit, 84 (41.6%) as least fit, and 45 (22.3%) as frail. Both univariate and multivariate models showed associations between frailty (defined as SLICC-FI > 0.21) and prevalent VF in the entire population (OR 5.76, 95% CI 2.53–13.12; P < 0.001) and in the premenopausal group (OR 4.29, 95% CI; P = 0.047). We also found an association between the SLICC-FI and low BMD. In conclusion, frailty assessed by SLICC-FI might be associated with VF and low BMD in mestizo females with SLE.