LIPOPROTEIN(A) AND APOLIPOPROTEIN(A) PHENOTYPES IN PATIENTS WITH END-STAGE RENAL-DISEASE

Objective: To evaluate the distribution pattern of apolipoprotein(a) [ Apo(a)] phenotypes in Koreans and the effect of dialysis modality on s erum lipoprotein(a) [Lp(a)] concentration according to apo(a) phenotyp e in patients with end-stage renal disease (ESRD). Design: Cross-secti onal study. Setting: A university hospital. Participants: 153 normal c ontrols, 99 hemodialysis (HD) patients and 82 continuous ambulatory pe ritoneal dialysis (CAPD) patients. Main outcome measures: Fasting seru m Lp(a), lipids, and apo(a) phenotypes were measured. Results: The fre quencies of the subjects with apo(a) phenotypes of high-molecular weig ht only, including S3, S4, or S5 or null type were 95.4% of control, 1 00% of HD patients, and 95.1% of CAPD patients. The frequent apo(a) ph enotypes in Koreans consisted of S4, S4S5, S5, and S5S5 isoforms. Sign ificant difference was found in serum Lp(a) concentration among contro ls and HD and CAPD patients [median (interquartile range): 0.05 g/L, ( 0.01 - 0.19); 0.19 g/L, (0.10 - 0.35); 0.63 g/L, (0.28 - 0.90), p < 0. 001]. Lp(a) levels in CAPD patients were significantly higher than in HD patients for all four common apo(a) isoforms found in Korean subjec ts. CAPD patients had higher total and LDL cholesterol levels, and hig her ApoB levels than HD patients. Significant differences were found i n serum albumin levels between controls and HD and CAPD patients (44 /- 3 g/L, 40 +/- 4 g/L, 32 +/- 7 g/L, respectively, p < 0.05). There w ere significant inverse correlations between serum albumin and Lp(a) ( r = -0.33, p < 0.01), total cholesterol (r = -0.31, p < 0.01), LDL (r = -0.39, p < 0.01) or ApoB (r = -0.35, p < 0.01) in ESRD patients. A s ignificant positive correlation was found between serum albumin and Ap oA(1) (r = 0.24, p < 0.01). Conclusion: These findings indicate that K oreans have mainly high-molecular weight apo(a) phenotypes and serum L p(a) is elevated in CAPD patients compared to HD patients for common a po(a) phenotypes, which may contribute to the frequent cardiovascular mortality in CAPD patients.