Impact of Treat-to-Target Therapy on Bone Mineral Density Loss in Patients With Rheumatoid Arthritis: A Prospective Cohort Study

BACKGROUND: Osteoporosis is a common comorbidity of rheumatoid arthritis (RA). Although RA disease activity has been demonstrated to be associated with bone loss in previous studies, most of them were cross-sectional studies and not in the context of treat-to-target (T2T) strategies. OBJECTIVES: This study aimed to evaluate the association of disease activity with bone mineral density (BMD) changes in the context of T2T strategies in a prospective RA cohort. METHODS: RA patients were enrolled from a prospective CENTRA cohort of Peking University First Hospital. The follow-ups have been scheduled every 3 to 6 months. BMD was repeated at baseline, 1 year, and then every other year. Demographics, baseline clinical features, laboratory data, and medications at each visit were recorded. Time-adjusted mean disease activity scores were adopted to reflect the overall disease activity during follow-up. The influence of univariable associations between predictors and BMD was investigated using linear regression. RESULTS: A total of 268 patients were included in our analysis. Their mean age was 50 (12.9) years, and 224 (83.6%) were women. The median (IQR) disease duration was 48.7 (107.6) months. Osteoporosis in the lumbar spine was observed in 23.1% of patients and 9.3% in the femoral neck at enrollment. Older age, higher SDAI score, and lower BMI were associated with osteoporosis at baseline. The proportion of patients who achieved DAS28-ESR, CDAI, and SDAI remission or LDA at the end of the first year was 71.5%, 68.8%, and 67.4%, respectively. Reevaluations of BMD at 1 year were applied to 144 patients. Mean decreases of BMDs were 1.75% at the lumbar spine and 1.40% at the femoral neck at 1 year from baseline, respectively. Patients who achieved remission had less yearly bone loss in the lumbar spine (p = 0.036). Female gender was identified as a risk factor in the multiple linear regression analyses, and lower disease activity and bisphosphonates were protective factors of continuous bone loss. CONCLUSION: Disease activity is associated with bone loss in RA patients in the context of T2T strategies, and those who achieved remission had less yearly bone loss.