Association of Serum Sclerostin Level, Coronary Artery Calcification, and Patient Outcomes in Maintenance Dialysis Patients

Objective: The objective of this study is to investigate the association between the serum sclerostin, the coronary artery calcification (CAC), and patient outcomes in maintenance dialysis patients. Methods: We performed a prospective cohort study of 65 maintenance dialysis patients in 2014, including 39 patients on peritoneal dialysis and 26 on hemodialysis, and followed up for 5 years. Parameters of mineral metabolism including bone-specific alkaline phosphatase, fibroblast growth factor 23, sclerostin, and other biochemical factors were determined at the baseline. Meanwhile, the CAC score was analyzed by cardiac computed tomography. Results: Serum sclerostin in hemodialysis patients was significantly higher than that in peritoneal dialysis patients (632.35 ± 369.18 vs. 228.85 ± 188.92, p < 0.001). The patients with CAC were older, receiving hemodialysis, lower Kt/V, and had longer dialysis vintage, as well as higher levels of serum 25-(OH)-vit D and sclerostin. In multivariate logistic regression analysis, older age and lower Kt/V were risk factors for CAC. The area under the receiver operating characteristic curves for prediction of CAC by sclerostin was 0.74 (95% confidence interval 0.605–0.878, p = 0.03), and the cutoff value of sclerostin is 217.55 pg/mL with the sensitivity 0.829 and specificity 0.619. After 5 years of follow-up, 51 patients survived. The patients in the survival group had significantly lower age, sclerostin levels, and low CAC scores than the nonsurvival group. Old age (≥60 years, p < 0.001) and high CAC score (≥50 Agatston unit, p = 0.031) were significant risk factors for the patient survival. Conclusions: Sclerostin is significantly elevated in dialysis patients with CAC. But sclerostin is not a risk factor for CAC. After 5 years of follow-up, patients in the survival group are younger and have lower sclerostin levels and CAC scores. But sclerostin levels are not independent risk factors for high mortality in dialysis patients.