Vitamin K status and vascular calcification biomarkers as determinants of carotid plaque in peritoneal dialysis: a...

Vitamin K deficiency impairs the activation of calcification inhibitors such as matrix Gla protein, promoting vascular calcification in CKD. Protein induced by vitamin K absence-II (PIVKA-II) is a filtration-independent marker of vitamin K status validated in hemodialysis, yet no data exist in peritoneal dialysis (PD).

Sixty prevalent PD patients at a single tertiary center were prospectively followed for 1 year. Serum PIVKA-II, dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP), and bone morphogenetic protein-2 (BMP-2) were measured at baseline and 12 months. Carotid plaque was assessed by ultrasonography. Independent predictors of plaque were identified by multivariable logistic regression and ROC analysis.

Carotid plaque was present in 36 patients (60%). Vitamin K deficiency (PIVKA-II >40 mAU/mL) was identified in 43.3% and was more prevalent in plaque-positive patients (55.5% vs 25.0%; p = 0.019). All three biomarkers were significantly elevated in the plaque group. Age (OR 1.26; 95% CI 1.07-1.42; p = 0.004) and PIVKA-II (OR 1.71; 95% CI 1.09-2.70; p = 0.022) independently predicted plaque. The area under the ROC curve was 0.766 (p = 0.001) with an optimal cutoff of 35.09 mAU/mL (sensitivity 86.1%, specificity 50.0%). Over 12 months, plaque prevalence rose to 70%; baseline BMP-2 was the sole predictor of new plaque development (p = 0.022).

PIVKA-II-assessed vitamin K deficiency is common in PD and independently associated with carotid plaque. A threshold of 35 mAU/mL may be more sensitive than the conventional 40 mAU/mL cutoff, supporting PIVKA-II screening and targeted supplementation trials in PD.