C-reactive protein to albumin ratio is an independent influencing factor of mortality in peritoneal dialysis patients / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the association between C-reactive protein (CRP)/albumin (ALB) ratio (CAR) and mortality in peritoneal dialysis (PD) patients.Methods:Clinical data of 791 PD patients in the Second Affiliated Hospital of Soochow University from January 1, 2004 to December 31, 2019 were retrospectively collected. According to the baseline quartiles of CAR, patients were divided into three groups low-level CAR group (CAR≤0.161 mg/g, n=264), medium-level CAR group (CAR 0.162-0.214 mg/g, n=263) and high-level CAR group (CAR≥0.215 mg/g, n=264). The clinical data among the three groups were compared. Follow-up was ended on March 31, 2020, or when the patients stopped PD due to death, shift to hemodialysis, renal transplantation or recovery of renal function. Kaplan-Meier survival curve, multivariate Cox proportional hazard model and Fine-Gray competing risk model were used to assess the relationship between CAR and all-cause mortality and cardiovascular and cerebrovascular mortality. The association between CAR, CRP, ALB, neutrophil to lymphocyte ratio (NLR), or platelet to lymphocyte ratio (PLR) and mortality in PD patients was compared by receiver-operating characteristic curve (ROC curve) analysis. Results:The age of the patients was (59.8±15.7) years old, and 447(56.5%) patients were males. 714(90.3%) patients had hypertension. 233(29.5%) patients had diabetes. 182(23.0%) patients had cardiovascular diseases. The median follow-up time was 55(31, 88) months. By the end of the follow-up, 236 deaths (29.8%) happened, and 95 patients (12.0%) died from cardiovascular and cerebrovascular diseases. Kaplan-Meier survival analysis results showed that the overall survival rate of the high-level CAR group was lower than those of the low-level CAR group and medium-level CAR group (Log-rank test χ2=109.50, P<0.001). Multivariate Cox regression analysis and Fine-Gray competing risk model revealed that CAR was independently correlated with all-cause mortality and cardiovascular and cerebrovascular mortality after adjusting for confounding factors ( HR=2.891, 95% CI 1.921-4.351, P<0.001; SHR=1.297, 95% CI 1.128-1.490, P<0.001). ROC curve analysis results showed that the area under the curve ( AUC) of CAR for predicting the risk of all-cause mortality in PD patients was 0.737(95% CI 0.700-0.774), which was superior to those of CRP ( AUC=0.643, 95% CI 0.599-0.687), NLR( AUC=0.608, 95% CI 0.563-0.653) and PLR ( AUC=0.554, 95% CI 0.508-0.601), and slightly lower than ALB ( AUC=0.752, 95% CI 0.716-0.788). The optimal cutoff value of CAR for death was 0.19 mg/g, with the sensitivity and specificity of 70.8% and 68.3%, respectively. Conclusions:Increasing CAR level is an independent risk factor of all-cause mortality and cardiovascular and cerebrovascular mortality in PD patients, and its correlation with mortality is higher than those of inflammatory parameters such as CRP, NLR and PLR.