Influencing factors of phase angle and prediction of clinical outcome in patients with non-dialysis chronic kidney disease

Abstract

Objective To investigate the influencing factors of phase angle (PhA) and its predictive ability of clinical outcome in patients with non-dialysis chronic kidney disease (CKD). Methods Sixty patients with non-dialysis CKD admitted to Department of Nephrology of Tongji Hospital from January to November 2019 were recruited in this study. All of them received hematuria biochemical test, nutritional risk screening and assessment, SF-36 quality of life survey, anthropometry, grip strength test and body composition detection. According to their PhA, they were divided into group A (PhA>4.5°) and group B (PhA≤4.5°), with 30 cases in each group. The correlation of phase angle with nutrition, inflammation, disease, moisture and other related indicators was analyzed, and the main influencing factors of PhA were analyzed with stepwise multiple linear regression analysis. Follow-up was conducted for 3 to 4 years to compare the survival of patients between the 2 groups. Results The blood total protein (TP), albumin (ALB), prealbumin (PAB), life quality score and grip strength were significantly better in group A than group B (P < 0.05). The high-sensitive C-reactive protein (CRP), total cholesterol (TC), low density lipoprotein (LDL), total 24h urinary protein (UTP), total 24h urinary albumin (UMA), urinary albumin creatinine ratio (ACR), modified SGA score and extracellular water (ECW/TBW) ratio were obviously lower in group A than group B (P < 0.05). Correlation analysis showed that TP, ALB and PAB were positively correlated with PhA (P < 0.05), and CRP, TC, LDL, UMA, modified SGA score and ECW/TBW ratio were negatively correlated with PhA (P < 0.05). Stepwise multiple linear regression analysis indicated that that ECW/TBW ratio was an independent factor affecting PhA. The mortality rate was high in group B (20.00%, 6/30) than group A (6.67%, 2/30) during follow-up. Cox regression survival analysis suggested that age and PhA were the main factors affecting the survival of non-dialysis CKD patients. The older the age, the higher the risk of death, with the risk of death being increased to 2.605 times for every 1° reduction of PhA. Conclusion In non-dialysis CKD patients, ECW/TBW ratio is an independent factor affecting PhA, and PhA is negatively correlated to ECW/TBW ratio. PhA can well predict the survival of these patients. And the smaller the phase angle is, the higher the mortality rate.

Keywords

• non-dialysis
• chronic kidney disease
• phase angle
• extracellular water ratio
• prediction