BackgroundBone mineral density (BMD) measured using dual-energy X-ray absorptiometry (DEXA) is one of the most important markers for osteoporosis diagnosis. The serum creatinine-to-cystatin C ratio (Cr/CysC) is in focus as a sarcopenia marker because it represents total muscle volume. Recently, Cr/CysC was suggested to have correlation with bone fragility fracture risk [1].ObjectivesThis study aimed to assess whether Cr/CysC is correlated with BMD.MethodsBMD at the lumbar spine (LS) and femoral neck (FN) were measured in women diagnosed with postmenopausal osteoporosis. Steroid induced osteoporosis patients were eliminated. Cr/CysC was assessed at the time. Clinical factors, such as age, concurrent rheumatoid arthritis treatment (RA), concomitant biological drug administration (BIO), body mass index (BMI), concurrent dementia treatment (dementia), number of comorbidities other than dementia (N.Com), frailty score (FS), bone fragility fracture (BFF), and drug intervention for osteoporosis (DI), were evaluated. Multivariate linear regression (MLR) was used to assess the correlation of these factors with BMD at each part. The relationships between Cr/CysC and other parameters were statistically evaluated using MLR. Additionally, the relationships between the BMD change at each part and parameters were evaluated in the same manner.ResultsThe study enrolled 207 subjects. BMD at the LS was significantly correlated with BMI and N.Com (p<0.01), whereas BMD at the FN was significantly negatively correlated with age and was positively correlated with BMI, BFF, Cr/CysC, and DI (p<0.01). Cr/CysC was significantly correlated with age, RA, BIO, dementia, FS, and BFF (p<0.01).After effect of age was corrected, BMD at the FN demonstrated significant positive correlation with Cr/CysC (p<0.01), whereas no statistical correlation demonstrated between BMD at the LS and Cr/CysC, Both BMD at the LS and the FN demonstrated significant positive correlation with BMI (p<0.05). No parameter significantly correlated with the BMD change at both the LS and FN (p<0.01).Table: Results of multivariate linear regression analysis for relationship between BMD in each part and parametersunivariate modemultivariate modeparametersCoefficientLCLUCLp-valueCoefficientLCLUCLp-valueage-0.002-0.0052.0x10-3
0.078
RA0.0650.0170.1149.00x10-4
0.034-0.0170.0840.19BIO0.036-0.0370.1090.338
BMI0.0180.0120.0243.54x10-8
0.0190.0130.0252.60x10-9
N.Com0.0080.0120.3456.70x10-6
0.010.0530.0143.00x10-5
Dementia-0.009-0.0620.0460.757Frailty score-0.015-0.0319.0x10-3
0.065bone fragility fracture-0.051-0.1080.0050.073
Cr/CysC0.2030.0062.0280.0440.086-0.110.2830.39Drug intervention-0.042-0.1030.0190.18
age-0.004-0.006-5.6415.72x10-8
-0.003-0.001-3.2131.55x10-3
RA0.0650.0340.0954.00x10-6
0.025-0.010.0590.16
BIO0.0590.0140.1050.0110.001-0.0490.0510.98
BMI0.0043.0x10-4
0.0080.0480.0042.0x10-3
0.0080.037N.Com0.0020.0051.130.26
Dementia-0.049-0.083-0.0154.78x10-3
0.008-0.0290.0440.69
Frailty score-0.019-0.028-0.0092.60x10-5
0.005-0.0070.0170.44
bone fragility fracture-0.068-0.103...