Lack of agreement between the plasma lipid-based criteria and apoprotein B for the diagnosis of familial combined hyperlipidemia in members of familial combined hyperlipidemia kindreds

Abstract

Our objective was to analyze the concordance between abnormally high-cholesterol and triglyceride concentrations and increased apoliprotein B (apoB) concentrations for considering subjects as affected in familial combined hyperlipidemia (FCHL) kindreds. Twenty-two FCHL families (n = 217) were included. There was a lack of agreement in the identification of the abnormal subjects when several cholesterol- and triglyceride-based criteria were compared against various apoprotein B-based criteria. The agreement, measured as kappa coefficients, between 14 lipid-based criteria and 8 apoB concentrations is reported. For the most frequently used criterion (> or = 90th percentile for cholesterol or triglyceride concentrations), the agreement was low for all apoB levels (kappa, 0.42 to 0.49). A concentration of triglycerides > or = 150 mg/dL and cholesterol > or = 200 mg/dL was the only criterion with a kappa value above 0.6; the acceptable agreement was found with an apoB concentration > or = 120 mg/dL (kappa = 0.604). In conclusion, the data reported here clearly show that a large degree of diagnostic uncertainty exists in the categorization as normal or abnormal of members of FCHL kindred. Different diagnostic criteria would result in conflicting results. This is a critical issue, depending on the diagnostic criteria used, completely different conclusions could result from the linkage analysis in the FCHL studies.