# Correlation between complement C3 level and abdominal aortic calcification in non-dialysis chronic kidney disease patients: a cross-sectional study

## TL;DR

This study finds that higher levels of complement C3 are linked to increased vascular calcification in non-dialysis chronic kidney disease patients.

## Contribution

The study reveals a J-shaped, non-linear relationship between C3 levels and vascular calcification in non-dialysis CKD patients.

## Key findings

- The third tertile of C3 (0.95–1.63 g/L) was significantly correlated with vascular calcification (OR = 2.06).
- Older age, hypertension, and hyperlipidemia are independent risk factors for vascular calcification in NDD-CKD patients.
- C3 has a predictive value with an AUC of 0.849 for vascular calcification.

## Abstract

Previous studies have shown that complement activation is associated with an increased risk of cardiovascular disease in patients with chronic kidney disease (CKD) on dialysis. This study aims to investigate the relationship between complement 3 (C3) and vascular calcification (VC) in non-dialysis-dependent CKD (NDD-CKD) patients.

Four hundred and fifty six NDD-CKD patients were enrolled from 2019 to 2022. C3 was measured by immunoscattering turbidimetry. According to the results of CT imaging, the patients were divided into the aorta vascular calcification group and the non-aortic vascular calcification group. Restricted cubic spline (RCS) analysis and logistic regression model were used to explore the association between C3 and VC in NDD-CKD patients. To assess how it predicted, a receiver operating characteristic (ROC) analysis was undertaken.

In NDD-CKD patients, the third tertile of C3 (0.95–1.63 g/L) was significantly correlated with VC (OR = 2.06, 95% CI: 1.13–3.83, p = 0.020). Older age and history of underlying diseases (hypertension, hyperlipidemia) are independent risk factors for VC in NDD-CKD patients. The area under the curve (AUC) of C3 for predicting VC was 0.849 g/L (sensitivity, 79.4%; specificity, 76.7%).

In patients with NDD-CKD, serum complement C3 exhibits a J-shaped relationship with vascular calcification, indicating a complex, non-linear association. Additionally, older age, hypertension, and hyperlipidemia were confirmed as independent risk factors.