Background Rate of vertebral body fractures and spinal deformities is 2-fold higher in RA patients compared to general population, compromising their quality of life.
Objectives To identify major risk factors of lumbar osteoporosis (OP) in RA female patients.
Methods The study included 220 RA female patients (ACR criteria), aged 20-75 y. (mean age – 57,1±10,8 y). An individual patient's file contained anthropometric parameters, social and demographic data, case history, clinical examination and lab findings, traditional OP risk factors, patient's joint status, info on concurrent diseases, pain intensity evaluation by VAS and evaluation of general health status. Bone mineral density (BMD) was measured using DEXA scan. DEXA T-score was used in post-menopausal women, and Z-score - in menstruating women.
Results Patients were grouped in two arms: patients with lumbar spine OP – 74 (33,6%) and without OP in the lumbar spine – 146 (66,4%). OP patients were somewhat older (59,8±10,2 vs 56±11,1 y., p=0,02 respectively), greater extent of functional impairment (HAQ >2) (43,4 vs 29,5%, RR =1,47, 95% CI 0,98–2,21, p=0,05), longer use of glucocorticosteroids (GC) (72 (36–110) vs 50 (12–95) mo, p=0,05), and at higher average daily doses during the previous year (6,3 (2,5–8,75) vs 5 (2,5–7,5) mg/day., p=0,01), as well as higher total GC dose 14,4 (5,4–25,8) vs 9 (2,4–16,5) g, p=0,02). RA activity by DAS28 and current radiographic lesions (Van der Heijde modification of Sharp method) was comparable in both groups. Analysis of traditional OP risk factors identified lower body weight in OP patients (64,4±10,6 vs 69,2±12,9 kg, p=0,01) and post-menopause status in the majority of them (94,6 vs 74%, RR =1,28, 95% CI 1,14–1,42, p=0,0001). Discriminate analysis identified the following major lumbar spine OP risk factors: RA duration, severe functional impairment by HAQ, average GC daily dose in the previous year and menopause. Based on identified factors and their coefficients a model was suggested (with area under the curve – AUC- equal to 0,784), allowing to predict lumbar spine OP with high precision, equal to 74.5%.
Conclusions Lumbar spine OP in RA female patients is to great extent predetermined by RA duration, higher degree of functional impairment by HAQ, average daily GS dose in the previous year and the menopause status.
Disclosure of Interest None declared