Combinations of valvular calcification and serum alkaline phosphatase predict cardiovascular risk among end-stage kidney disease patients.

Background: Valvular calcification (VC) refers to the calcified valvular remodeling associated with kidney dysfunction, especially end-stage kidney disease (ESKD). ESKD patients with VC had significantly higher cardiovascular risk than those without. Factors interacted with VC regarding prognostic prediction in this population were seldom investigated. We aimed to examine the potential synergetic effects of VC and alkaline phosphatase (Alk-P) on ESKD patients' cardiovascular risk and mortality.

Methods: ESKD patients undergoing hemodialysis were prospectively enrolled from a medical center in 2018. We identified patients with echocardiography and available serum Alk-P levels. Cox proportional hazard regression was performed to analyze the risk of major adverse cardiovascular events (MACEs), cardiovascular and overall mortality among 4 participant groups (with or without VC versus low or high Alk-P levels). The models were further adjusted for age, sex, and clinical variables.

Results: Of the 309 ESKD patients, 38, 46, 112, and 113 had no VC with low Alk-P, no VC with high Alk-P, VC with low Alk-P, and VC with high Alk-P, respectively. After adjusting for age and sex, patients with VC and high Alk-P had a higher risk of developing MACE, cardiovascular and overall mortality (HR, 3.07, 3.67, 3.65; 95% CI 1.38-6.84, 1.1-12.24, 1.29-10.36, respectively). Patients with VC and high Alk-P remained at higher risk of MACE (HR, 2.76; 95% CI 1.17-6.48) than did those without VC and with low Alk-P.

Conclusion: Serum Alk-P could be used to identify a subgroup of ESKD patients with elevated cardiovascular risk among those with VC.