A LOWER HIP BONE MINERAL DENSITY IS INDEPENDENTLY ASSOCIATED WITH A HIGHER LEVEL OF DISEASE DAMAGE IN MESTIZO PERUVIAN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background: The prevalence of osteoporosis is greater in SLE patients than in the general population, however, there is few studies analyzing the association with bone mass density and damage in hispanic SLE patients. Objectives: To determine if bone mineral density (BMD) is independently associated with level of disease damage in patients with Systemic Lupus Erythematosus (SLE). Methods: In a cross-sectional single center study, we evaluated 117 consecutive SLE patients, who were seen at the Rheumatology department of our hospital. SLE was defined using the ACR criteria. BMD was measured by DXA at hip and lumbar spine. A chart review, clinical evaluation and laboratory exams were performed. Also, an interview, in order to evaluate calcium intake and other osteoporosis risk factors, was carried out. We defined damage using SLICC ACR damage index (SDI); the point of severe osteoporosis was exclude for the analysis. Disease activity was measured using SLEDAI. For the univariated analysis we performed Spearman's correlation, after that, we performed a linear regression model adjusted to disease activity, accumulated dose of prednisone, age, gender, disease duration, previous fracture, history of delivery, calcium intake and body mass index. Results: One hundred and seventeen SLE patients with a mean age of 41.85 (SD: 13.95) years, 95.7% female were included. Almost all of them were mestizo, only one was African Latin-American and one was amerindian. Mean total hip BMD was 0.88 (SD: 0.14) g/cm and mean lumbar spine BMD was 0.92 (SD: 0.13) g/cm. There were statistically significant correlation between lumbar spine, total hip BMD and age (R: -0.240, p: 0.013 and R: -0.205, p: 0.038, respectively), accumulated dose of prednisone (R: -0.341, p: 0.009, R: -0.407, p: 0.002), and SDI (R: -0.385, p<0.001, R:-0.374, p<0.001). Body mass index and disease duration only correlate with total hip BMD (R:0.412, p<0.001, R: -0.213, p: 0.031 respectively). There were no statistically significant correlation between total hip or lumbar spine BMD and SLEDAI, history of delivery and calcium intake. There were no significant difference in lumbar spine or total hip BMD between male and female (0.93 vs 0.92, p: 0.85 and 0.93 vs 0.87, p:0.19 respectively). Previous fracture was significantly associated with lower total hip BMD (0.80 vs 0.87, p: 027), but not with lumbar spine BMD (0.88 vs 0.93, p: 0.22). After adjustment for disease activity, accumulated dose of prednisone, age, gender, disease duration, history of delivery, calcium intake, body mass index and previous fracture the SDI remained associated with a lower total hip BMD (B: -0.270, p: 0.031) but not with lumbar spine BMD (B: -0.238, p: 0.089). Conclusion: A lower hip BMD is associated with a higher level of disease damage as measured by SDI in our SLE patients, independently of disease activity, accumulated dose of prednisone, age, gender, disease duration, calcium intake, history of delivery, body mass index and previous fracture. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 69, supplement 3, year 2010, page 688Session: SLE, Sjögren's and APS – clinical aspects (other than treatment) (Abstracts accepted for publication )