EFFECT OF INCREASING SERUM-ALBUMIN ON SERUM LIPOPROTEIN(A) CONCENTRATION IN PATIENTS RECEIVING CAPD

Lipoprotein(a) [Lp(a)], an independent risk factor for atherosclerotic cardiovascular disease in the general population, is known to be elev ated in patients with renal disease accompanied by hypoalbuminemia suc h as nephrotic syndrome and end-stage renal disease. In this study, th e role of hypoalbuminemia in the elevation of serum Lp(a) was investig ated in 20 continuous ambulatory peritoneal dialysis (CAPD) patients w ith serum albumin below 3.5 g/dL. The patients were divided into two g roups. In group 1 (n = 10), fasting serum Lp(a) and albumin were measu red before, after repeated infusion of 20% albumin 100 mt three times per week for 2 weeks, and 4 weeks after withdrawal of albumin infusion . In group 2 (n = 10), serum albumin and Lp(a) were measured similarly without albumin infusion. C-reactive protein was monitored in both gr oup as an indicator of acute-phase reactant. Serum Lp(a) was also meas ured in 20 age-and sex-matched normal controls. Apolipoprotein(a) [apo (a)] phenotype was determined in all the subjects. CAPD patients as a whole (n = 20; median, 70.2 mg/dL; interquartile range, 45.0 to 86.2 m g/dL) had higher serum Lp(a) than normal controls (n = 20; median, 9.9 mg/dL; interquartile range, 2.4 to 24.3 mg/dL) (P < 0.0001), although the distribution of apo(a) phenotype was similar. Serum albumin in gr oup 1 increased from 2.6 +/- 0.5 g/dL to 3.5 +/- 0.6 g/dL (P < 0.0005) at the end of repeated infusion of albumin, whereas serum Lp(a) decre ased from 73.7 mg/dL (range, 43.2 to 89.0 mg/dL) to 25.6 mg/dL (range, 10.7 to 71.7 mg/dL) (P < 0.01). Four weeks after withdrawal of albumi n infusion, serum albumin decreased again to 2.9 +/- 0.5 g/dL (P < 0.0 01), whereas serum Lp(a) increased to 65.2 mg/dL (range, 43.3 to 106.0 mg/dL) (P < 0.05). Serum albumin in group 2 was 2.8 +/- 0.6 g/dL, 3.0 +/- 0.4 g/dL, and 2.9 +/- 0.7 g/dL, respectively. The change of serum Lp(a) was not significant (67.0 mg/dL [range, 46.8 to 84.8 mg/dl], 62 .8 mg/dL [range, 45.1 to 81.0 mg/dl], and 63.0 mg/dL [range, 44.7 to 7 4.0 mg/dL]). C-reactive protein was stable during the study period in both groups. These findings support the hypothesis that hypoalbuminemi a is one of the important trigger factors in the elevation of serum Lp (a) in CAPD patients. (C) 1997 by the National Kidney Foundation, Inc.