The Influence And Correlation Of Hemodialysis Filtration Frequency On Cognitive Impairment In Hemodialysis Patients

Objective:Cognitive impairment(CI)is a common complication in patients with maintenance hemodialysis(MHD),and its pathogenesis remains unclear.Our previous studies have found that the species richness of intestinal flora in MHD patients is significantly increased,and metabolites in vivo are significantly changed,which is related to cognition.Therefore,the intestinal microflora plays a crucial role in the twoway communication between the guts and the brain.Thus,we hypothesize that hemodiafiltration(HDF)could alleviate cognitive impairment by removing more toxin in MHD patients.Our study was aimed to investigate the effects of different frequency HDF treatment on cognitive function in MHD patients and examine the influencing factors of cognitive impairment.Methods:This study was a cross-sectional,multicenter cohort study.We recruited MHD patients over 18 years old who received dialysis three times a week and regular high-throughput HD or HDF for more than 6 months.According to their HDF frequency,the patients were divided into three groups:once a month(n=45),once a week(n=3 5)and three times a week(n=20).Demographic characteristics such as age,sex,dialysis duration and primary disease were recorded.Hemoglobin(Hb),Kt/v,white blood cells(WBC),platelets(PLT),creatinine(Cr),urea nitrogen(BUN),sodium(Na),potassium(K),phosphorus(P),calcium(Ca),parathyroid hormone(PTH),total cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDL-C),highdensity lipoprotein cholesterol(HDL-C),blood albumin(ALB),B-type brain natriuretic peptide precursor(NT-pro BNP),hypersensitive C-reactive protein(hsCRP),β2-microglobulin(β2-MG)and other laboratory results were measured.Cognitive function was assessed using the Montreal Cognitive Assessment Scale(MoCA)and the quality of life(QOL)was examined by the 36 Short Form Health Survey(SF-36).Depending on the type and distribution of data,t test,Mann-Whitney U test,ANOVA test,Kruskal-Wallis H test and Chi-square test were undertaken.Spearman Correlation was used to analyze the correlation between cognition and HDF frequency.The risk factors of CI were determined by binary Logistic regression analysis,and ROC curve was performed to evaluate the predictive value of laboratory indicators on CI.Results:440 patients with MHD were screened and assessed according to the inclusion criteria,and 100 patients were enrolled,62%of whom had cognitive impairment.The median MoCA score of all patients was 24.00(20,26.75),the lowest score was 23.00(17,26)in once a month HDF group,the medium score was 25(21,28)in once a week HDF group,and the highest score was 26.00(23,27.5)in three times a week HDF group.The difference among the three groups was statistically significant(P=0.012).Spearman Correlation was used for cognition and HDF frequency,and there was a significant correlation between them(r=0.298,P=0.003).Serum potassium and β2-MG levels in once a month HDF group were significantly higher than those in other two groups(all P<0.001),and there was no significant difference in serum potassium andβ2-MG levels between once a week HDF group and three times a week HDF group.The concentration pattern of serum calcium and calcium-phosphorus among the three group were aligned and both showed in an orderly manner,with the lowest level observed in group received the least HDF and elevated with the increasing frequency of HDF treatment.(all P<0.001,post-hoc comparison P<0.05).The patients were divided into cognitive impairment(CI)group and normal cognitive function(NCF)group according to MoCA score.There were no significant differences between CI group and NCF group in gender,dialysis duration,residual urine volume,underlying diseases,previous diseases,vascular access,Kt/v,WBC,Hb,PLT,TG,HDL-C,NT-pro BNP,hs-CRP,β2-MG,Ca,K,Na,BUN,Cr,etc.Age,BMI,cardiovascular complications,calcium-phosphorus product,serum phosphorus,TC and LDL-C in CI group were significantly higher than those in NCF group(P<0.001,P=0.031,β=0.037,P=0.038,P=0.027,P=0.009,P=0.026,respectively).The results of CI group were significantly lower than NCF group in education level,ALB and hs-CRP(P<0.001,P=0.029,P=0.023,respectively).Age,education level and LDL-C level were independent predictors of cognitive impairment in MHD patients.With the diagnosis of CI,the area under ROC curve(AUC)of age,education level and LDL-C level were 0.793,0.737 and 0.633,and the cut-off values were 52.5,13.5 and 2.875,respectively.Combining the three indicators yielded an AUC of 0.852.In addition,the median total QOL score of MDH patients was 69,which was at a low level.The QOL score of once a month HDF group was significantly lower for general health(GH)when compared to the other groups(P=0.007).And the QOL score for vitality(VT)in three times a week HDF group was significantly higher than the other groups(P=0.026).Conclusion:1.It may be more effective to improve MHD patients’ cognitive levels with high frequency HDF.2.Cognition in MHD patients is affected by age,education level,and LDL-C level independently.