title: Biological variation of lipoprotein(a) in a diabetic population. Analysis of the causes and clinical implications.
abstract: The aims of the present study were to evaluate the biological variability of lipoprotein(a) (Lp(a)) in diabetic patients and to investigate the biological sources of this variability. Lp(a) was measured by ELISA in four serum specimens collected in 3-month intervals from 70 patients. The other parameters analyzed were: total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, HbA and albumin excretion rate. The overall biological within-subject variance (CVb) was 31.7%, and it was inversely correlated with Lp(a) serum levels. According to the initial ranges of Lp(a) serum levels (< 15, 15-30 and > 30 mg/dl) the CVb were 42.3%, 24.1% and 23.7%, respectively. In multivariate analysis the total intra-individual coefficient of variation (CVt) of triglycerides and the CVt of the albumin excretion rate (AER) were independently associated with the CVb of Lp(a) (R2 = 0.54). The intra-individual biological variation of Lp(a) produced a misclassification of 20% of diabetic patients for cardiovascular risk attributable to this lipoprotein. In conclusion, the higher biological variability of Lp(a) observed in diabetic patients suggests that a single determination could be inaccurate to assess the cardiovascular risk associated with this lipoprotein, at least in those patients in whom serum levels are near the cut-off considered as risk for cardiovascular disease (> 30 mg/dl). Finally, triglycerides and AER are the main factors influencing Lp(a) serum levels in the diabetic population.
authors.affiliation: Diabetes Research Unit, Hospital General Vall d'Hebron, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Hernández
authors.forename: Gemma
authors.initials: G
authors.lastname: Francisco
authors.forename: Pilar
authors.initials: P
authors.lastname: Chacón
authors.forename: Jordi
authors.initials: J
authors.lastname: Mesa
authors.forename: Rafael
authors.initials: R
authors.lastname: Simó
mesh_terms: D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000652:urine; D000911:Antibodies, Monoclonal / Q000276:immunology; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood* / Q000652:urine; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000652:urine; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006441:Hemoglobin A / Q000032:analysis; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood* / Q000276:immunology / Q000652:urine; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D014280:Triglycerides / Q000097:blood
chemical_list: D000911:Antibodies, Monoclonal; D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D017270:Lipoprotein(a); D014280:Triglycerides; D006441:Hemoglobin A; D002784:Cholesterol