ECTS Abstracts (2015) 1 OC6.3

The effects of daily teriparatide on the spine and femoral strength assessed by a finite element analysis of clinical computed tomography scans in rheumatoid arthritis patients

Kumiko Ono1, Satory Ohashi2, Hiroyuki Oka3, Yuho Kadono1, Tetsuro Yasui1, Yasunori Omata1, Naoko Shoda1 & Sakae Tanaka1

1Department of Orthopaedic Surgery, Faculty of medicine, The university of Tokyo, Tokyo, Japan; 2Department of Orhopaedic Surgery, Sagamihara Hospital, National Hospital Organization, Kanagawa, Japan; 3Department of Joint Disease Research, 22nd Century Medical and Research Center, Faculty of medicine, The university of Tokyo, Tokyo, Japan.

Background: To evaluate the quantitative effects in RA patients who are treated with TPTD after 12 months by several methods.

Methods: Twenty-seven RA patients were enrolled in this prospective study. All patients who were receiving TPTD were evaluated according to changes in two bone turnover markers (serum procollagen type 1 N-terminal propeptide [P1NP] and, tartrate-resistant acid phosphatase-5b [TRACP-5b]) from baseline to 1, 3, 6 and 12 months. They were assessed according to bone mineral density (BMD) by dual X-ray absorptiometry (DXA) and bone strength by quantitative computed tomography (CT) at baseline. They were re-evaluated after 12 months. Nonlinear finite element analysis (FEA) was performed on the CT scans to compute an estimate of spinal and femoral-fall configuration predicted bone strength (PBS) by FEA.

Results: Patients were aged 68.2 years and their duration of symptoms was 12.2 years. The majority of subjects had moderate disease activity (mean baseline 28-joint disease activity score, 3.0±1.3). The mHAQ scores median were 0.8. On average, PINP (baseline, 1, 3 and 6 months) was 42, 141, 144 and 153 μg/l, TRACP-5b was 423, 527, 583 and 601 mU/dl. Patients had significantly greater levels of serum PINP and TRACP-5b (P<0.05 compared with baseline) at all points measured. On average, BMD-spine (baseline and 12 months) was 0.89, 0.94 g/cm2 (P<0.01) (median change 6.3%), BMD-femoral neck was 0.62, 0.62 g/cm2 (P=0.31) (median change 1.4%), PBS-spine was 3508, 4070 N (P<0.01) (mean change 19.8%), and femoral PBS-fall was 1428, 1441 N (P=0.2) (mean change 1.6%).

Conclusions: Our results show that TPTD can increase BMD and FEA on RA patients, and indicate that bone loss can be prevented in patients with RA by TPTD. FEA should detect changes of TPTD effects more sensitive than DXA. We will have to follow these effects in longer term.

Disclosure: The authors declared no competing interests.