Evaluation of the Chylomicron-TG to VLDL-TG ratio for Type I Hyperlipoproteinemia diagnostic.

BACKGROUND The aim of this study is to confirm the diagnostic performance of the Chylomicron to Very Low Density Lipoproteins Triglycerides (CM/VLDL-TG) ratio, the Triglycerides to Cholesterol ratio (TG/TC) and a dichotomic rule including the Tryglicerides to Apolipoprotein B (TG/APOB) ratio for the presence of Type I Hyperlipoproteinemia (HPLI) in patients with severe hypertriglyceridemia (sHTG) that were at high risk for Familial Chylomicronemia Syndrome (FCS). METHODS Two cohorts (Derivation and Validation) of patients with sHTG were included in the study. Anthropometric, clinical, biochemical and genetic data were obtained. The CM/VLDL-TG, TG/TC and TG/APOB ratios were calculated. Finally, a diagnostic performance study was developed to establish Sensitivity, Specificity and cut-offs by a ROC curve analysis in the Derivation Cohort as well as Agreement and Predictive Values in the Validation Cohort. RESULTS Patients with FCS in both cohorts showed an earlier presence in pancreatitis, greater number of acute pancreatitis episodes and lower BMI. FCS patients also showed higher ratios of CM/VLDL-TG, TG/TC and TG/APOB ratios, whereas their HDL-C, LDL-C and APOB levels were lower than in non-FCS patients. Sensitivity and Agreement were low for both the TG/TC and TG/APOB ratios, although Predictive Values were good. The CM/VLDL-TG ratio showed greatest sensitivity, specificity, Agreement and Predicitve Values for cut-off of 3.8 and 4.5. CONCLUSIONS Our results suggest that in subjects at high risk of FCS a total serum TG/TC ratio or TG/APOB ratio are feasible to initially screen for HLPI; however, a CM/VLDL-TG ratio ≥ 4.5 is a better diagnostic criterion for HPLI.