Association Between Lipoprotein Combine Index and All-cause and Cardiovascular Mortality in Patients Undergoing Peritoneal Dialysis: A Multicenter Retrospective Cohort Study

Caixia Yan¹Qing Zhan¹Xu Qingdong²Fenfen Peng³Yueqiang Wen⁴Tian Na⁵Xiaoyang Wang⁶Xiaoran Feng⁷Xianfeng Wu⁸Juan Wu⁹Ning Su¹⁰Xingming TANG¹¹Qian Zhou¹²Jianlong Lu¹Yanbing Chen¹Xiaojiang Zhan^1*

• ¹The First Affiliated Hospital of Nanchang University, Nanchang, China
• ²Jiangmen Central Hospital, Jiangmen, China
• ³Zhujiang Hospital of Southern Medical University, Guangzhou, China
• ⁴Guangzhou Medical University Second Affiliated Hospital, Guangzhou, China
• ⁵General Hospital of Ningxia Medical University, Yinchuan, China
• ⁶The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
• ⁷Jiujiang Third People's Hospital, Jiujiang, China
• ⁸Shanghai 6th Peoples Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
• ⁹Zhejiang Provincial People's Hospital, Hangzhou, China
• ¹⁰Sun Yat-sen University Sixth Affiliated Hospital, Guangzhou, China
• ¹¹Songshan Lake Central Hospital of Dongguan, Dongguan, China
• ¹²The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China

Background: Cardiovascular disease (CVD) is the leading cause of death in patients undergoing peritoneal dialysis (PD). The lipoprotein combine index (LCI), integrating total cholesterol, triglycerides, LDL-C and HDL-C, may better reflect atherogenic burden than traditional single-lipid measures. We hypothesized that higher baseline LCI would be independently associated with increased risks of all-cause and cardiovascular mortality in incident PD patients. Methods: In this multicenter retrospective cohort, 1,986 incident PD patients from six centers (2005-2021) were analyzed. LCI was divided into quartiles (Q1-Q4). Outcomes were all-cause and CVD mortality. Missing covariates were imputed. Centre-stratified Cox models estimated hazard ratios (HRs), and restricted cubic splines assessed nonlinear trends. Results: Over a median 35-month follow-up, 662 deaths occurred, including 328 CVD deaths. Higher LCI quartiles showed progressively higher mortality. For all-cause death, adjusted HRs (95% CI) were 1.41 (1.10-1.80), 1.59 (1.25-2.02) and 1.70 (1.34-2.15) for Q2-Q4 vs Q1. For CVD death, HRs were 1.45 (1.03-2.02), 1.29 (0.92-1.82) and 1.68 (1.22-2.33). A non-linear pattern was observed for all-cause mortality, with risk increasing when LCI exceeded ~20. The association with CVD mortality was stronger in younger patients (<60 years) (P interaction = 0.048). Conclusion: Higher baseline LCI independently predicted all-cause and CVD mortality in PD patients, supporting its usefulness for risk stratification and age-specific lipid management.