The Correlation Between Serum Ca/Mg Ratio And Nutritional Status In Patients With Diabetic Kidney Disease Undergoing Maintenance Hemodialysis

Objective Protein-energy wasting(PEW)is one of the common complications in MHD patients.Magnesium(Mg)is an important cation in human body and is involved in various metabolic processes in vivo.Low blood magnesium is closely related to diabetes and PEW.Studies had shown that the serum Ca/Mg ratio is a better predictor of cardiovascular events and all-cause mortality compared with serum mg in MHD patients,but whether the serum Ca/Mg ratio is assoc-iated with PEW in patients with diabetic kidney disease still unclear.This stu-dy evaluated the correlation between serum Ca/Mg ratio and PEW in patients with diabetic kidney disease undergoing HD.MethodsThis study was a cross-sectional study involving in 3 hemodialysis units that included diabetic hemodialysis patients with PEW as subjects.Patients were divided into three groups according to the level of the serum Ca/Mg ratio,which are low serum Ca/Mg ratio group(Ca/Mg ratio<3.5)、middle Ca/Mg ratio group(Ca/Mg ratio 3.5～4.5)and high Ca/Mg ratio group(Ca/Mg ratio> 4.5).Biochemical index and anthropological measurement index were detected before dialysis.Subjective global assessment of nutrition(SGAN),malnutrition-inflammation score(MIS)and handgrip strength(HGS)were used to comprehensively assess patient nutritional status.The prevalence of PEW in the three units’ study population in this study was calculated,and the differences in general demographic data,biochemical indicators,anthropometric indicators,MIS and HGS in each group were compared.The correlation factors were analyzed by Spearman analysis.Results⑴ The prevalence of patients with DKD undergoing MHD in the three hemodialysis units was 88.2%.The average age was 63.3±9.2 years,the dialysis vintage was 4～115months,the average BMI was 23.62±3.40 kg/m2.⑵ In this study,43 cases in low serum Ca/Mg ratio group,51 cases in middle serum Ca/Mg ratio group and 63 cases high serum Ca/Mg ratio group weredetermined according to the grouping criteria.Comparing the general demographic data of the subjects in each group,such as age,sex,marital status,education level,family income and payment pattern of medical expenses,the difference was no statistical significant(P>0.05),suggesting that the groups were comparable.⑶ There was no significant change in Hb,ALB,TC,SCR,bun,UA,TF,UIBC and TIBC among the three groups,and there was no statistical difference between the three groups(P>0.05).With the increase of the serum Ca/Mg ratio,hs-CRP and i PTH increased gradually,and PA decreased gradually.Compared with low serum Ca/Mg ratio group and middle serum Ca/Mg ratio group,hs-CRP in high serum Ca/Mg ratio group had statistical difference(P<0.05),and i PTH and PA had significant statistical difference(P<0.01).⑷ The results of anthropometric measurement showed that there was no statistical difference in BMI among the three groups(P<0.05);among the three indexes of TSF,MAC and MAMC,only MAMC was different among the three groups.The analysis of variance between groups showed that compared with low serum Ca/Mg ratio group,high serum Ca/Mg ratio group was significantly lower(18.25 ± 5.33 vs 21.42 ± 5.61),with statistical difference(P<0.05).⑸ The results of this study showed that with the increase of the serum Ca/Mg ratio,the MIS score gradually increased,and the difference between high serum Ca/Mg ratio group and low serum Ca/Mg ratio group(16.51±1.54 vs 10.42±1.36),high serum Ca/Mg ratio group and middle serum Ca/Mg ratio group(16.51±1.54 vs14.73±1.62)was statistical significant(P<0.05);with the increase of the serum Ca/Mg ratio,HGS was significantly lower in high serum Ca/Mg ratio group compared to low serum Ca/Mg ratio group(28.63±7.45 vs 32.31±7.52),the difference between high serum Ca/Mg ratio group and middle serum Ca/Mg ratio group(28.63±7.45 vs31.42±8.32)was statistically significant(P<0.05).⑹ The serum Ca/Mg ratio was tested by Spearman correlation test for hs-CRP,i PTH,PA,MAMC,MIS and HGS in blood of study subjects.The results showed that the serum Ca/Mg ratio was positively correlated with hs-CRP(r=0.462,P<0.01),i PTH(r=0.573,P<0.01),MIS score(r=0.625,P<0.01),and negatively correlated with PA level(r=-0.741,P<0.01),MAMC(r=-0.663,P<0.01),and HGS(r=-0.554,P<0.01),but it was not correlated with serum Alb,Hb,TC,UA,BMI and other biochemical indicators.ConclusionsThe serum Ca/Mg ratio is associated with PEW in DKD patients undergoing MHD.The serum Ca/Mg ratio is one of the good nutrition indicators to evaluate the severity of PEW in such patients.