Screening osteoporotic femoral neck without measuring bone mineral density with the use of tartrate resistant acid phosphatase-5b and serum-creatinine-to-cystatin C ratio in Japanese postmenopausal women.

Background: Screening osteoporosis in Japanese postmenopausal women is an important subject for preventing bone fragility fracture (BFF). Measuring bone mineral density (BMD) is included in the criteria for osteoporosis diagnosis. However, it has not gained popularity.

Methods: BMD of lumbar spine (LS) and femoral neck (FN) were measured, the serum creatinine-to-cystatin C ratio (Cr/CysC), tartrate-resistant acid phosphatase-5b (TRACP-5b), body mass index (BMI) were also simultaneously measured. These subjects had no potential secondary osteoporosis factors or concomitant drug administration for osteoporosis (pSubjects; primary subjects). Best subsets regression analysis (BeStR) was evaluated for determining the statistically significant factors, and multivariate regression analysis (MLR) was used to assess the correlation of these factors with BMD at each part. Relationship between osteoporotic criteria whether T score≤-2.5 and each factor was also evaluated at each part with binary logistic regression analysis (BLR). Cut-off index (COI) at each part was determined, and sensitivity and specificity were evaluated in pSubjects and in subjects with whom potential secondary osteoporosis factors were included (sSubjects).

Results: BMI and Cr/CysC had a significant influence on BMD at the LS with BeStR, whereas only BMI demonstrated significant correlation with BMD both with MLR and BLR, with 22.7 of COI and sensitivity and specificity of 48.7% and 94.7%, respectively, in pSubjects with 60 and 49.1% and 87.5%, respectively, in sSubjects with 83. At the FN, Cr/CysC, BMI, and TRACP-5b significantly influenced BMD, whereas all these factors demonstrated significant correlation with BMD. Cr/CysC and TRACP-5b demonstrated significant correlation with T score≤-2.5 in BLR. With COI that was made in combination with these factors and subjects' age, sensitivity and specificity were 67.7% and 82.4%, respectively, in pSubjects and 55.8% and 82.8%, respectively, in sSubjects.

Conclusions: These results suggested that BMI, TRACP-5b, and Cr/CysC may be realistic surrogate markers for screening osteoporosis in Japanese postmenopausal women.