Effect of hyperphosphatemia on patency rate of arteriovenous fistula of patients with late fistula dysfunction/failure after reoperation

Abstract

Objective: To investigate the effect of hyperphosphatemia on long-term patency of arteriovenous fistula (AVF) of patients with late fistula dysfunction/failure after reoperation. Methods: The study was carried out in the Department of Nephrology of the First Affiliated Hospital of Tsinghua University between March 2012 and March 2013. A total of 136 maintenance hemodialysis patients[73 males, 63 females, with an average age of (57.7±16.1) years]with late AVF dysfunction/faliure who received AVF reoperation were enrolled in the study. After follow-up for 3 years, 118 patients were left and divided into two groups: fistula dysfunction group (n=38), fistula patency group (n=80). Patients were aslo divided into two groups according to the blood phosphorus level: the blood phosphorus >1.78 mmol/L group (n=53) and the blood phosphorus ≤1.78 mmol/L group (n=65). t test was used to compare the serum phosphorus levels of patients with dysfunction group and fistula patency group. Patency rate was calculated by survival analysis method and log-rank test was used to compare secondary patency rate between groups of blood phosphorus >1.78 mmol/L and blood phosphorus ≤1.78 mmol/L. Multivariate Cox regression was used to analyze the influencing factors. Results: The average blood phosphorus level was significantly higher in dysfunction group[(1.87±0.42) mmol/L vs (1.65±0.39) mmol/L, P=0.008], and patency rate was significantly lower in patients of blood phosphorus>1.78 mmol/L group than that in patients of blood phosphorus ≤1.78 mmol/L (42.2% vs 60.4%, P=0.009). Blood phosphorus>1.78 mmol/L (RR=2.527, 95% CI: 1.272-5.023, P=0.008), diabetes (RR=2.667, 95% CI: 1.339-5.313, P=0.005) and C-reactive protein (CRP)>5 mg/L (RR=2.749, 95% CI: 1.324-5.710, P=0.007) were risk factors affecting secondary patency rate of internal fistua. Conclusion: Hyperphosphatemia is an independent risk factors for the patency rate of AVF after reoperation in hemodialysis patients.