Clinical significance of serum cystatin C-to-creatinine ratio as a surrogate marker for incident osteoporotic fracture predictions.

Background: Detection of appropriate indicators is valuable for preventing incidental osteoporotic fractures. We statistically evaluated the significance of serum cystatin C-to-creatinine ratio (CysC/Cr) as a surrogate marker for incident major osteoporotic fractures (MOF) prediction. Methods: Eligible patients with simultaneous measurement of CysC/Cr and bone mineral density in the lumbar spine and proximal femur were selected, and their fracture histories until 5 years after baseline were observed in the retrospective area cohort data. Patients who were followed up until termination or the first osteoporotic fracture were included, and loss of follow-up or death was excluded. Candidate risk factors for osteoporotic fractures were tested for risk ratios using a cox regression analysis. Receiver operating characteristic tests were performed on factors with significantly higher risk ratios and evaluated with Kaplan-Meier survival analysis to determine the hazard ratios of the factors. Results: A total of 175 patients of whom 28 had incident MOF, 38 men, and 137 women, were enrolled. The mean age was 70.2 years. A significantly higher risk ratio was shown in the presence of prevalent MOF, hyper fall-ability, lifestyle-related diseases, chronic kidney diseases ≥ Grade3a, and higher CysC/Cr. All parameters had cutoff indices and showed significantly higher hazard ratios. Conclusions: These results suggested that CysC/Cr may be a predictive marker of incident osteoporotic fractures. It might work as a screening tool for MOF risk.