Effect of body composition on dialysis quality(Kt/V): a single center study / 中华肾脏病杂志

ABSTRACT

Objective To investigate the relationship between body composition and adequacy of dialysis,and analyze the related risk factors for inadequate delivery of hemodialysis.Methods In a prospective clinical trial,two different methods determining dialysis dose were simultaneously appliedKt/Vdau (conventional method with Daugirdas' formula) and Kt/Vbem [online clearance monitoring (OCM) measurement with Ⅴ measured by body composition monitor (BCM)].Using the value of 1.27 as the boundary,the patients were divided into two groupsKt/Vbcm ＜ 1.27 group and Kt/Vbcm≥ 1.27 group.Clinical indices were compared between the two groups.Multiple linear regression was applied to analyze the potential impact factors of the difference between Kt/V values calculated by the two methods.Receiver operator characteristic (ROC) curve was applied to analyze meaningful factors.Results A total of 138 maintenance hemodialysis patients with age of (54.9±12.7) years old were enrolled,and 55.1％ of them were males.There was no significant difference between Kt/Vdau and Kt/Vbcm [1.432(1.235,1.718) vs 1.434 (1.244,1.642),P=0.823].Kt/Vdau was incidentally prone to falsely high values due to operative errors,whereas in these cases OCM-based measurement Kt/Vbcm delivered realistic values.An excellent correlation was observed between Kt/Vdau and Kt/Vbcm;the mean difference was 0.07,95％CI (-0.66-0.79);the correlation coefficient was 0.842(0.821-0.862).The patients in Kt/Vbcm≥ 1.27 group had older age,lower body mass index (BMI),lower height and weight,lower total body water (TBW),lower extracellular water,lower intracellular water,and lower lean tissue index (LTI) compared to those in Kt/Vbcm ＜ 1.27 group.Excellent correlations were observed between Kt/Vbcm and TBW or LTI (r=-0.834,P ＜ 0.001;r=-0.721,P ＜ 0.001).ROC curve analysis showed that the sensitivity and specificity of predicting inadequate delivery of hemodialysis were 87.1％ and 86.5％,with a threshold of 30 L for TBW.It also showed that the sensitivity and specificity of predicting inadequate delivery of hemodialysis were 60.4％ and 94.6％,with a threshold of 11.05 kg/m2 for LTI.Conclusions BCM can give more accurate parameters of urea distribution volume,thus modifying the result of Kt/V.TBW and LTI are important risk influencing factors for inadequately dialysis,and special attention should be paid to patients with TBW ＞ 30 L or LTI ＞ 11.05 kg/m2.