Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan.
J Bone Miner Metab. 2019 Mar;37(2):282-291. doi: 10.1007/s00774-018-0913-4. Epub 2018 Feb 20.
Coexistence of chronic kidney disease (CKD) is regarded as a risk for osteoporotic fracture particularly in postmenopausal women, not only because of increased parathyroid hormone level but also uremic sarcopenia. We examined the relationships of cystatin C-based glomerular filtration rate (eGFRcys) and creatinine-based GFR (eGFRcr), as well as their ratio with occurrence of osteoporotic fracture in postmenopausal osteoporotic women. This cross-sectional study included 555 postmenopausal women with osteoporosis. eGFRcr and eGFRcys were simultaneously measured, while occurrence of osteoporotic fracture was obtained by a medical chart review. Patients with osteoporotic fractures (n = 211) exhibited significantly lower levels of physical activity, eGFRcr, eGFRcys, and eGFRcys/eGFRcr ratios, while a higher percentage was CKD stage 3 or more, estimated by eGFRcr or eGFRcys (CKDcys), than those without (n = 344). Lower eGFRcys, but not lower eGFRcr, was independently associated with osteoporotic fracture in the entire cohort and that association was retained in CKDcys patients. Of great interest, higher eGFRcr was associated with osteoporotic fracture independent of eGFRcys in CKDcys patients. Furthermore, lower eGFRcys/eGFRcr ratio was independently associated with osteoporotic fracture in both CKDcys patients and the entire cohort. eGFRcys reduction might be associated with osteoporotic fracture in postmenopausal osteoporotic women, indicating the involvement of renal osteopathy in its occurrence. Furthermore, the association of higher, but not lower, eGFRcr with osteoporotic fracture in CKDcys cases might be explained by underestimation of renal dysfunction by eGFRcr resulting from decreased muscle mass and quality in those patients.
慢性肾脏病（CKD）共存被认为是绝经后妇女骨质疏松性骨折的危险因素，不仅因为甲状旁腺激素水平升高，还因为尿毒症性肌肉减少症。我们研究了胱抑素 C 为基础的肾小球滤过率（eGFRcys）和肌酐为基础的 GFR（eGFRcr），以及它们的比值与绝经后骨质疏松妇女骨质疏松性骨折发生的关系。这项横断面研究纳入了 555 名绝经后骨质疏松症患者。同时测量了 eGFRcr 和 eGFRcys，通过病历回顾获得了骨质疏松性骨折的发生情况。患有骨质疏松性骨折的患者（n=211）表现出明显较低的体力活动水平、eGFRcr、eGFRcys 和 eGFRcys/eGFRcr 比值，而 CKDcr 或 eGFRcys（CKDcys）估计的 CKD 分期 3 期或更高的比例则更高（n=344）。在整个队列中，较低的 eGFRcys，但不是较低的 eGFRcr，与骨质疏松性骨折独立相关，而这种相关性在 CKDcys 患者中仍然存在。有趣的是，在 CKDcys 患者中，较高的 eGFRcr 与骨质疏松性骨折独立相关，而不依赖于 eGFRcys。此外，在 CKDcys 患者和整个队列中，较低的 eGFRcys/eGFRcr 比值与骨质疏松性骨折独立相关。eGFRcys 减少可能与绝经后骨质疏松妇女的骨质疏松性骨折有关，表明肾性骨病在其发生中的参与。此外，在 CKDcys 病例中，较高的 eGFRcr 与骨质疏松性骨折相关，而不是较低的 eGFRcr，这可能是由于这些患者肌肉质量和功能下降导致 eGFRcr 低估了肾功能障碍。
