| Objective The relationship between serum bicarbonate and residual kidney function（RKF）has been determined in patients with chronic kidney disease（CKD）.However,the association between serum bicarbonate and RKF has gotten little attention in patents with peritoneal dialysis（PD）,and to our knowledge,just a few studies have analyzed hemodialysis,kidney transplant,loss to follow-up,and all-cause death events as competing risks for RKF loss among PD patients.Therefore,this study aims to investigate the effect of serum bicarbonate level on RKF and to evaluate the clinical value of serum bicarbonate on RKF loss in PD patients.Methods Data of PD patients who underwent peritoneal dialysis catheterization in the Department of Nephrology,the First Affiliated Hospital of Anhui Medical University from June 1st,2018 to June 1st,2021.All patients were followed up until RKF loss or the date of study termination（January 1st,2022）.All patients were divided into RKF retention group and RKF loss group based on the presence or absence of RKF loss during the follow-up period,and clinical characteristies,laboratory tests and dialysis-related indexes of the two groups were compared.In addition,on the basis of the median time-averaged serum bicarbonate（TA-Bic）levels,the study population was again divided into T1（low TA-Bic）and T2（high TA-Bic）groups,and the difference in RKF loss between the two groups was compared using the Kaplan-Meier method.The Cox proportional hazards regression analyses,and the multivariable competing risk model were performed to evaluate the factors associated with RKF loss in patients with peritoneal dialysis.Results（1）A total of 127 PD patients were enrolled in this study with age at PD onset of（47.89±13.77）years old,of which 67 were females（52.8%）,the median TA-Bic level was 24.2 mmol/L,and the median follow-up was 14.0（9.0,20.0）months.There were60（47.2%）participants with RKF loss by the end of the study with a median follow-up time of 14 months.The Time-averaged serum bicarbonate（TA-Bic）,baseline residual glomerular filtration rate（r GFR）,serum calcium,24h urine output,and total CCr levels in patients without RKF were significantly lower than those in patients with RKF.（2）The Kaplan-Meier curve showed a statistically significant difference in prognosis between the two groups,indicating that the cumulative RKF preservation rate of PD patients in T1 group was significantly lower than that in T2 group（P<0.001）.（3）The univariate Cox regression analysis showed that the TA-Bic levels,baseline r GFR,24h urine output,total CCr and total Kt/V may be related to the loss of RKF in PD patients.After adjusting for multiple confounders,the risk of RKF loss in T1 group was 4.871 times higher than that in T2 group（95%CI:2.672-8.882,P<0.001）.The higher levels of BMI（95%CI:1.030-1.238,P=0.009）was an independent risk factor for the risk of RKF loss,and higher baseline r GFR（95%CI:0.442-0.719,P<0.001）and advanced age（95%CI:0.950-0.995,P=0.015）were independent protective factors.（4）After fully accounting for competing events such as hemodialysis（HD）,kidney transplant,loss to follow-up,and all-cause death,the results of the multivariable competing risk model showed that the risk of RKF loss in the T1 group was 3.583 times higher than that in the T2 group（95%CI 2.006-6.401,P<0.001）.In addition,the cumulative incidence curve demonstrated that the risk of complete RKF loss was significantly higher in the T1 group of PD patients than in the T2 group（P<0.001）.Conclusion The lower serum bicarbonate levels are closely related to the loss of RKF in PD patients.More monitoring and management of serum bicarbonate levels may be of great value in improving the long-term prognosis of PD patients. |
