No correlation between lipoprotein(a) and biochemical markers of renal function in the general population

Context. - Lipoprotein(a) (Lp(a)) is receiving major emphasis as an independent risk factor for cardiovascular disease. Results of studies on Lp(a) in patients with impaired renal function are contradictory, and no information is available on the association between Lp(a) and estimated glomerular filtration rate and cystatin C. Objective. - To evaluate the potential relationships among the biochemical markers creatinine, estimated glomerular filtration rate, and cystatin C and their association with Lp(a) in patients with impaired renal function. Design. - We performed a retrospective analysis using the database of our laboratory to retrieve results of Lp(a), creatinine, and cystatin C tests performed on consecutive outpatients referred by general practitioners for routine blood testing during the last year. Results. - Cumulative results for all of the above-mentioned variables were retrieved for 150 adults older than 35 years. After stratifying Lp(a) values according to thresholds of creatinine, estimated glomerular filtration rate, and cystatin C, no significant differences in Lp(a) concentration were observed in subjects with abnormal values of these biochemical markers. The prevalence of Lp(a) values greater than or equal to 300 mg/L was not significantly different in subjects with biochemical markers suggestive of impaired renal function, as compared with those without such markers. In multivariable linear regression analysis, none of the parameters tested was significantly associated with Lp(a). Conclusions. - We suggest that unless renal function is completely compromised, measurement of biochemical markers of renal function might be relatively unimportant to improve clinical usefulness of Lp(a) testing.