Sclerostin is not associated with cardiovascular event or fracture in kidney transplantation candidates

Background: Sclerostin, a bone-derived protein, has been linked to cardiovascular calcifications in chronic kidney disease (CKD). The aim of this study was to investigate the associations between sclerostin and mineral and bone disorder in CKD, specifically whether sclerostin levels could predict cardiovascular event, fracture, or all-cause mortality. Materials and methods: Kidney transplantation candidates (n = 157) underwent computed tomography scans of the chest, abdomen, and pelvis. Calcification scores were calculated for coronary arteries, thoracic aorta, and the aortic and mitral valves. Volumetric bone mineral density (BMD) was measured at the spine and hip. Sclerostin and markers of bone turnover were determined from fasting blood samples. Results: Compared to patients with a calcification score of 0, sclerostin levels were higher in patients with calcifications at the coronary arteries (+23%, p < 0.001) and the thoracic aorta (+ 27%, p = 0.001), but not in patients with calcifications at the aortic (+1%, p = 0.85) or mitral (+ 8%, p = 0.20) valves. During a median follow-up of 3.7 years, 28 patients had a major cardiovascular event, 19 patients sustained a fragility fracture, and 32 patients died. Sclerostin levels above the median did not predict major cardiovascular event (p = 0.15), fracture (p = 0.58), or mortality (p = 0.65). Conclusion: Sclerostin was positively associated with the presence of vascular calcifications, but was not predictive of events associated with mineral and bone disorder in a cohort of kidney transplantation candidates.