Abstract: Background　The mortality of maintenance hemodialysis（MHD） patients is significantly higher than that of the general population.Acid-base balance disorder is one of the important factors causing protein energy consumption，inflammation，endocrine disorders and abnormal bone metabolism.Better control and maintenance of acid-base balance in the body is helpful for the survival rate of patients.Current research focuses more on the bicarbonate level before hemodialysis，however，there are relatively few studies on other indicators that affect acid-base balance，such as changes in blood pH before and after dialysis，and its impact on the clinical prognosis of MHD patients.Objective　To investigate the relationship between the blood pH difference between postdialysis and predialysis and the all-cause death and cardiovascular death in MHD patients.Methods　A total of 162 patients with stable MHD who underwent hemodialysis at the Hemodialysis Center of the People's Hospital of Ningxia Hui Autonomous Region from March 2014 to June 2014 were selected as the research subjects.General data of the patients were collected，including gender，age，dialysis age，follow-up time，serum albumin，hemoglobin，fasting blood glucose，high sensitivity C-reactive protein（hs-CRP），blood calcium，blood phosphorus，full parathyroid glands，B-type brain natriuretic peptide，creatinine，urea nitrogen，uric acid，urea clearance index（spKt/V），total cholesterol，triacylglycerol，low density lipoprotein，high density lipoprotein，serum iron，total iron binding capacity，ferritin，systolic blood pressure，diastolic blood pressure，pH before and after dialysis，CO2 before and after dialysis，HCO3- before and after dialysis.According to the median of ΔpH，patients were divided into ΔpH<0.099 5 group and ΔpH≥0.099 5 group.The patients were followed up for a long time，once per 3 months.The end of the follow-up event was the death of the patient （including all-cause death and cardiovascular disease death）.The deadline for follow-up was May 2019.Analyze the relationship between the pH difference of patients and all-cause deaths and deaths from cardiovascular diseases.Results　In the end，142 patients were enrolled，including 39 all-cause deaths and 26 cardiovascular deaths.Compared with patients in ΔpH<0.099 5 group，patients had a higher serum phosphorus，creatinine，urea nitrogen，uric acid，spKt/V and postdialysis pH in ΔpH≥0.099 5 group，but predialysis pH，postdialysis CO2 and predialysis HCO3-，all-cause mortality and cardiovascular mortality were lower.COX regression analysis showed that high sensitive CRP〔HR=3.736，95%CI（1.699，8.213），P=0.001〕，predialysis diastolic pressure〔HR=0.372，95%CI（1.699，0.760），P=0.007〕，and ΔpH〔HR=0.496，95%CI（0.252，0.974），P=0.042〕are independent risk factors for all-cause mortality.Morover，high sensitive CRP〔HR=2.464，95%CI（1.063，5.711），P=0.035〕 and ΔpH〔HR=0.412，95%CI（0.178，0.955），P=0.039〕 are independent risk factors for death from cardiovascular disease in MHD patients.Kaplan-Meier survival analysis showed all-cause deaths and deaths from cardiovascular diseases in the ΔpH≥0.099 5 group were lower than those in the ΔpH<0.099 5 group （P<0.05）.Conclusion　Patients with MHD patients with larger ΔpH have a lower risk of all-cause death and cardiovascular disease death，and more adequate correction of blood pH may help improve the survival rate of MHD patients.

Key words: Renal dialysis, Death, Blood pH, Kidney diseases

摘要： 背景　维持性血液透析（MHD）患者的死亡率较普通人群显著升高，酸碱平衡紊乱是造成蛋白质能量消耗、炎症、内分泌紊乱和骨代谢异常的重要因素之一，更好地控制并维持体内酸碱平衡有助于提高患者的生存率。目前的研究更多的聚焦于血透析前HCO3-水平，其他影响酸碱平衡的指标，如透析前后血pH值变化及其对MHD患者临床预后影响的研究相对较少。目的　探讨MHD患者透析后与透析前血pH值变化程度与全因死亡、心血管疾病死亡的关系。方法　选取2013年3月—2013年6月于宁夏回族自治区人民医院血透中心病情稳定的162例MHD患者为研究对象，收集患者一般资料，包括性别、年龄、透析龄、随访时间、血清蛋白、血红蛋白、空腹血糖、高敏C反应蛋白（hs-CRP）、血钙、血磷、全段甲状旁腺素、B型脑钠肽、肌酐、尿素氮、尿酸、尿素清除指数（spKt/V）、总胆固醇、三酰甘油、低密度脂蛋白、高密度脂蛋白、血清铁、总铁结合力、铁蛋白、收缩压、舒张压、透析前后pH值、透析前后CO2、透析前后HCO3-。根据ΔpH中位数，将患者分为ΔpH<0.099 5组和ΔpH≥0.099 5组。对患者进行随访，1次/3个月，随访终点事件为患者死亡（包括全因死亡及心血管疾病死亡），随访截止时间为2019年5月。分析患者ΔpH与全因死亡、心血管疾病死亡的关系。结果　最终入选142例患者，全因死亡患者39例，心血管死亡26例。ΔpH≥0.099 5组血磷、肌酐、尿素氮、尿酸、SpKt/V、透析后pH值高于ΔpH<0.099 5组，透析前pH值、透析后CO2、透析前HCO3-、全因死亡率和心血管疾病死亡率低于ΔpH<0.099 5组（P<0.05）。多因素COX回归分析显示，hs-CRP〔HR=3.736，95%CI（1.699，8.213），P=0.001〕、舒张压〔HR=0.372，95%CI（0.182，0.760），P=0.007〕、ΔpH〔HR=0.496，95%CI（0.252，0.974），P=0.042〕与MHD患者全因死亡相关；hs-CRP〔HR=2.464，95%CI（1.063，5.711），P=0.035〕、ΔpH〔HR=0.412，95%CI（0.178，0.955），P=0.039〕与MHD患者心血管疾病死亡相关。Kaplan-Meier生存分析显示ΔpH≥0.099 5组患者全因死亡、心血管疾病死亡患者累积生存率均低于ΔpH<0.099 5组（P<0.05）。结论　MHD患者ΔpH较大，其全因死亡和心血管疾病死亡的风险更低，更充分的纠正血pH值可能有助于提高MHD患者的生存率。

关键词: 肾透析, 死亡, 血pH, 肾疾病