Effect of initial dialysis dose on survival in peritoneal dialysis patients

Objective To compare the effect of initial daily dialysis dose of 8 L versus 6 L on the survival rate in peritoneal dialysis (PD)patients with different baseline residual renal function.Methods From January 2012 to December 2019,504 PD patients treated over 3 months were enrolled retrospectively.According to the baseline value of estimated glomerular filtration rate (eGFR),they were divided into three groups.That was eGFR<4 mL·(min·1.73m²)^-1in group A (n=52),4-6 mL·(min·1.73m²)^-1in group B(n=156) and≥6 mL·(min·1.73m²)^-1in group C (n=296).Primary etiologies,laboratory parameters at Month 1 post-PD,peritoneal transport functions and clinical outcomes were recorded.The survival rate of different initial daily dialysis doses (6 L versus 8 L)was compared among 3 groups.Results The 5-year survival rates of three groups were 64.0%,79.0% and 71.6% respectively.And there was no statistical difference (P=0.306).Kaplan-Meier analysis indicated that,except for group C,median survival time of PD patients with 6 L initial dialysis dose was lower than that with 8 L in group A/B (48.78±7.18 versus 95.46±7.18 months,χ²=5.439 P=0.020,79.78±5.87 versus 99.66±4.09 months,χ²=4.509,P=0.034).No significant difference existed in survival time of patients with 8 L/d with different timing of dialysis (χ²=0.280,P=0.870).Multivariate Cox regression analysis revealed that diabetes mellitus,baseline hypoalbuminemia and advanced age were independent risk factors for patient mortality.The initial daily dialysis dose of 8 L was a protective factor (OR=0.577,95%CI 0.336-0.990,P=0.037).Peritoneal transport function and baseline eGFR had no effect upon the prognosis of PD patients.Conclusions For PD patients with poor residual renal function at the initiation of PD,low dialysis dose independently predicts patient mortality.And 8L initial daily dialysis dose yields no greater survival benefits than 6 L/d in those with eGFR≥6 mL·(min·1.73m²)^-1 at the initiation of dialysis.