Biochemical correlates of lipoprotein(a) in a general adult population. Possible implications for cardiovascular risk assessment.
BACKGROUND
Evidence has been provided that lipoprotein(a) (Lp(a)) may be an important cardiovascular risk factor. Recognition of potential Lp(a) variability associated with common diseases, such as diabetes, chronic renal dysfunction, impaired liver function and acute/chronic inflammation, is important to optimize the clinical usefulness of this measurement.


METHODS
We performed a retrospective analysis on our Laboratory Information System to retrieve results of fasting plasma glucose (FPG), creatinine, albumin, high sensitivity-C reactive protein (Hs-CRP) and Lp(a) tests, which were performed on all outpatients referred by general practitioners for routine blood testing during the last 5 years.


RESULTS
Cumulative results for all of the above parameters were retrieved for 1,195 adults. After stratifying Lp(a) results according to the respective threshold values of albumin, estimated glomerular filtration rate (e-GFR), FPG and Hs-CRP, a significant difference was observed only among subjects with increased Hs-CRP levels (170 mg/l vs. 125 mg/l; P < 0.001). The frequency of Lp(a) values > or =300 mg/l was greater in those with increased Hs-CRP levels (36 vs. 26%; P = 0.037)-but not in those with abnormal values of albumin, e-GFR or FPG-compared with their counterparts with normal values of these parameters. In multiple regression analysis, age (r = 0.112; P < 0.001), Hs-CRP (r = 0.102; P = 0.001) and e-GFR (r = 0.106; P = 0.003) were independent predictors of Lp(a).


CONCLUSIONS
The evaluation of laboratory markers of glucose homeostasis and liver function seems unnecessary when measuring Lp(a) for cardiovascular risk assessment. Conversely, Hs-CRP and probably GFR might be of clinical value to identify individuals whose serum Lp(a) levels can be transiently or chronically increased.
Lippi
Giuseppe
G
Sezione di Chimica Clinica, Dipartimento di Scienze Morfologico-Biomediche, Università degli Studi di Verona, Ospedale Policlinico G.B. Rossi, Piazzale Scuro 10, 37134, Verona, Italy. ulippi@tin.it
Targher
Giovanni
G
Franchini
Massimo
M
Guidi
Gian Cesare
GC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D001786:Blood Glucose / Q000032:analysis; D002097:C-Reactive Protein / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology / Q000503:physiopathology; D003404:Creatinine / Q000097:blood; D003955:Diagnostic Tests, Routine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D017270:Lipoprotein(a) / Q000032:analysis*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012709:Serum Albumin / Q000032:analysis; D019564:Unnecessary Procedures; D055815:Young Adult
D015415:Biomarkers; D001786:Blood Glucose; D017270:Lipoprotein(a); D012709:Serum Albumin; D002097:C-Reactive Protein; D003404:Creatinine