Daily teriparatide treatment is associated with a significant increase in lumbar spine predicted bone strength (PBS) and bone mineral density (BMD) in patients with rheumatoid arthritis (RA) and osteoporosis, according to study results published in Journal of Bone and Mineral Research.
While BMD is an important factor affecting fracture risk, bone quality is also a major determinant of bone strength and fracture risk.
The objective of the current study was to quantitatively assess the impact of teriparatide treatment on PBS, as determined by quantitative computed tomography-based finite-element analysis, and on BMD determined by dual-energy x-ray absorptiometry. Furthermore, among patients showing an increase in PBS and BMD, univariate regression analysis was completed to identify clinical determinants associated with increases in these variables.
The study cohort included 39 patients (mean age, 69 years; 35 women) with RA and osteoporosis. All patients had available data on BMD by dual x-ray absorptiometry and PBS by quantitative computed tomography-based finite-element analysis of lumbar spine and proximal femur measured at baseline and after 6 and 12 months.
After 6 months of treatment, mean increases in lumbar spine PBS and BMD from baseline were 9.9% and 4.0%, respectively. At 12 months, lumbar spine PBS and BMD were 14% and 8.6%, respectively. However, in the femoral neck there was no significant change in PBS or BMD at 6 or 12 months of teriparatide treatment.
Univariate logistic regression showed that increases in N-terminal type I procollagen propeptide (P1NP) at 1 and 3 months were significantly associated with increased lumbar spine PBS after 12 months of teriparatide treatment. No factors were significantly associated with a 12-month increase in lumbar spine BMD. Researchers noted that the threshold value for increased P1NP at 1 month for increased PBS at 12 months was 75 μg/L.
The study had several limitations, including the small sample size, lack of control group, and relatively short follow-up period.
“Although this study was preliminary in nature, PBS based on [quantitative computed tomography-based finite-element analysis] appears useful for assessing the therapeutic effects of daily teriparatide in patients [with] RA. We believe that these new findings will play a central role in deciding treatments for osteoporosis in patients [with] RA,” the researchers concluded.
Ono K, Ohashi S, Oka H, et al. Evaluations of daily teriparatide using finite-element analysis over 12 months in rheumatoid arthritis patients. Published online September, 4, 2020. J Bone Miner Metab. doi:10.1007/s00774-020-01146-6