The Value Of Non-HDL-C And Lp(a) In Differential Diagnosis Between Familial Hypertriglyceridemia And Familial Combined Hyperlipidemia

Objective: To investigate the differences of Non-HDL-C and Lp(a)between familial hypertriglyceridemia(FHTG)and familial combined hyperlipidemia(FCHL)and explore either Non-HDL-C and Lp(a)can be used for differential diagnosis between FHTG and FCHL or not.And to identify the merits and dismerits of NonHDL-C,Lp(a)and TG,TC,LDL-C,HDL-C in diagnosis of FHTG and FCHL families.Methods: Selecting 48 families which came from the sub-topics of the fifteen major science and technology special(2002BA711A08-17).According to the diagnostic criteria of pedigrees,the 48 families were divided into FHTG group,FCHL group,and control group.In FHTG and FCHL groups,according to dyslipidemia or not divided into dyslipidemia and normal blood lipid group.Firstly,This study compared the TG,HDL-C,LDL-C,Non-HDL-C and Lp(a)levels among the three groups to identify whether Non-HDL-C and Lp(a)can be used as the new indicators for the differential diagnosis between FHTG and FCHL pedigrees.If Non-HDL-C and Lp(a)can be used for the differential diagnosis between FHTG and FCHL,then the ROC curve was used to analyze the cut-off values of FHTG and FCHL pedigrees.Furthermore,the difference between Non-HDL-C and LDL-C and the correlation between Non-HDL-C and LDL-C were analyzed according to the TG level in the FHTG and the FCHL pedigrees.Finally,according to the ROC curve,this study analyzed the merits and dismerits of all indicators in the differential diagnosis between FHTG and FCHL.Results:1.1.The lipid levels of FHTG group,FCHL group and control group:The levels of TG,TC and Non-HDL-C in FHTG pedigree with dyslipidemia group and in FCHL pedigree with dyslipidemia group were both significantly higher than those in control group(P <0.01 or P <0.05).Compared with control group,thelevels of HDL-C,LDL-C and Lp(a)have no difference in FHTG pedigree with dyslipidemia group(P> 0.05),but those in the FCHL pedigree with dyslipidemia group have the higher levels than the control pedigree group(P <0.01 or P <0.05).The levels of TG,TC and Non-HDL-C in FHTG pedigree with dyslipidemia group and in FCHL pedigree with dyslipidemia group were higher than those in FHTG pedigree with normal lipid group and in FCHL pedigree with normal lipid group(P <0.01 or P <0.05).Both in the FHTG and FCHL,the level of Lp(a)have no difference between the dyslipidemia group and the normal lipid group(P> 0.05).Compared with the respective normal lipid group,the levels of HDL-C and LDL-C have no difference in FHTG pedigree with dyslipidemia group(P> 0.05),but those in the FCHL pedigree with dyslipidemia group have the higher levels(P <0.01 or P<0.05).The levels of TC,HDL-C,LDL-C and Non-HDL-C in FHTG pedigree with dyslipidemia were significantly higher than those in FCHL pedigree with dyslipidemia(P <0.01),but the level of TG in FHTG pedigree with dyslipidemia was significantly higher than that in FCHL pedigree with dyslipidemia(P < 0.01 or P<0.05).The level of Lp(a)have no difference in both FHTG and FCHL pedigree with dyslipidemia(P> 0.05).2.Comparison the difference of Non-HDL-C and LDL-C in FHTG and FCHL with differential levels of TGThere were no significant difference in the difference of Non-HDL-C and LDL-C between the TG critical group and the TG high level group in FHTG and FCHL pedigrees(P> 0.05).However,The difference of Non-HDL-C and LDL-C was significantly higher in the very-high-level group than the TG critical group and the TG high level group(P <0.01).3.The correlation of LDL-C and Non-HDL-C with differential levels of TGIn the TG critical group,Non-HDL-C was highly correlated with LDL-C both in FHTG and FCHL pedigrees(r = 0.946,P <0.001;r= 0.925,P <0.001).In the TG high level group,Non-HDL-C was also highly correlated with LDL-C both in FHTG and FCHL pedigrees(r = 0.899,P <0.001;r= 0.896,P <0.001).In the very-high-level group,non-HDL-C was lowly correlated with LDL-C both in FHTG and FCHL pedigrees(r = 0.346,P>0.05;r= 0.321,P>0.05).4.The value of LDL-C and Non-HDL-C in differential diagnosis between FHTG and FCHLAccording to the ROC curve,the cut-off values of TG,TC,LDL-C and Non-HDL-C for differential diagnosis of FHTG and FCHL were 3.500 mmol/L,5.665mmol/L,3.575 mmol/L and 4.525 mmol/L respectively.The area under the curve was0.786,0.970,0.953 and 0.972 respectively.The sensitivity and specificity of TG were78.3% and 58.6%.The sensitivity and specificity of LDL-C in differential diagnosis were 89.1% and 93.1%.The sensitivity and specificity of LDL-C in differential diagnosis were 80.4% and 96.6%.The sensitivity and specificity of Non-HDL-C were89.1% and 96.6%.Conclusion:1.In addition to TC,TG and LDL-C,Non-HDL-C can be used as a new indicator in differential diagnosis between FHTG and FCHL pedigrees.2.With the increasing of TG,the difference of Non-HDL-C and LDL-C were increased,but the correlation between Non-HDL-C and LDL-C were decreased or even disappeared,and could be regarded as two independent lipid markers.FCHL pedigree was considered when Non-HDL-C?4.525 mmol / L,and FHTG pedigree was considered when Non-HDL-C <4.525 mmol / L.3.The sensitivity and specificity of Non-HDL-C in differential diagnosis between FHTG and FCHL pedigrees were higher than TC,TG and LDL-C,and the value of differential diagnosis may be superior to traditional blood lipid index,such as LDL-C.