#82 Serum zinc level is associated with aortic arch calcification in patients with incident dialysis

Abstract

Abstract Background and Aims Aortic calcification is one of predictors of cardiovascular (CVD) events. Several studies show association between zinc deficiency and aortic calcification in patients with chronic kidney disease (CKD). However, there are few studies in patients with advanced CKD. Therefore, we investigated associations between serum zinc (s-Zn) levels and aortic arch calcification (AAC) in patients with incident dialysis. Method We analyzed data from 776 consecutive patients with CKD who started dialysis at our hospital between January 2013 and December 2022. We excluded 71 patients who were supplemented with zinc or who were not measured laboratory data including serum zinc at the time of dialysis initiation. AAC is graded from 0 (no calcification) to 3 on chest X-ray, as follows: grade 0, no visible calcification; grade 1, < 50% calcification in the arch; grade 2, > 50% calcification; grade 3, circumferential calcification. We defined grade 2 or 3 as severe calcification. Results The median s-Zn levels were 51, 47 and 44 μg/dL in patients with grade 0, 1 and 2-3 on AAC, respectively (p < 0.0001). The optimal cutoff value for s-Zn levels was 48 μg/dL in receiver operating characteristic (ROC) curves analysis. In multivariate analysis, low s-Zn level (s-Zn < 48 μg/dL) was independently associated with AAC [OR 2.36 (95% CI 1.55–3.60), p < 0.0001)], especially with severe AAC [OR 4.59 (95% CI 2.46–8.59), p < 0.0001)]. Addition to s-Zn level in a model with established factors on AAC improved the C-index (0.812 to 0.824, p = 0.0181), net reclassification improvement (NRI) (0.397, p < 0.0001) and integrated discrimination improvement (IDI) (0.020, p < 0.0001). More robust findings for the C-index (0.856 to 0.878, p = 0.0077), NRI (0.591, p < 0.0001) and IDI (0.045, p < 0.0001) were observed on severe AAC. Conclusion Low s-Zn level was independently associated with severity of AAC, also in patients with incident dialysis.