Comparison of the effect of 18-month daily teriparatide administration on patients with rheumatoid arthritis and postmenopausal osteoporosis patients

Summary Patients with rheumatoid arthritis showed greater response to 18-month administration of daily teriparatide especially in the increase of bone formation markers at 1 month and femoral neck bone mineral density at 18 months compared to postmenopausal osteoporosis patients. Introduction The aim of this study was to evaluate the effects of 18-month administration of daily teriparatide (TPTD) in osteoporosis patients with rheumatoid arthritis (RA) by comparing that of postmenopausal osteoporosis patients (Porosis). Methods The effects of TPTD were examined between RA ( n = 70; age 68.4 years; disease activity score assessing 28 joints with CRP [DAS28-CRP] 2.8; rheumatoid factor [RF] positivity 75.5 %) with 77.1 % of prior bisphosphonate (BP), 84.3 % of oral prednisolone (PSL) (4.4 mg/day at baseline), 25.7 % of biologics, and Porosis ( n = 62; age 71.3 years) with 77.4 % of prior BP. Results Femoral neck (FN) bone mineral density (BMD) increase at 18 months was significantly greater in RA compared to Porosis (4.7 vs. 0.7 %, P = 0.038), whereas it was 9.7 versus 7.9 % ( P = 0.736) in the lumbar spine (LS). The increase of bone formation markers (bone alkaline phosphatase [bone ALP] and N-terminal type I procollagen propeptide [PINP]) at 1 month were all significantly greater in RA compared to Porosis. A multivariate logistic regression analysis revealed that the significant indicator of 18-month BMD increase in RA was a 3-month increase of under-carboxylated osteocalcin (ucOC) for LS ( β = 0.446, P = 0.005) and baseline ucOC for FN ( β = 0.554, P = 0.001), in which both showed significant negative correlation with baseline PSL dose. Conclusions RA showed greater response to daily TPTD administration, especially in the increase of bone formation markers at 1 month and FN BMD increase at 18 months compared to Porosis.