SERUM-LIPOPROTEIN (A) CONCENTRATIONS IN PATIENTS UNDERGOING CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

Lipoprotein (a) is a subspecies of low-density lipoprotein which possesses as part of its protein moiety a mutant form of plasminogen termed apolipoprotein (a), and which may be closely related to the risk of ischaemic heart disease and cerebral infarction. We have investigated the serum concentrations of lipoprotein (a) and other lipoproteins in 24 male patients on CAPD and compared them to healthy men (n = 100) and to age-matched healthy controls (n = 38). The most striking finding was a substantial elevation of serum lipoprotein (a) in CAPD patients in whom it was 46.9 (2.2-168) mg/dl (median and range) compared to 9.0 (< 0.6-87.4) mg/dl in healthy control group and 6.7 (< 0.6-84.2) mg/dl in age-matched controls (both P < 0.001). Patients, when compared to healthy men, also had significantly increased serum triglycerides (median and range, 1.94 (0.55-8.00) versus 1.24 (0.36-4.40)mmol/l; P < 0.001), very-low-density lipoprotein cholesterol (median and range, 0.98 (0.10-3.71) versus 0.46 (0.10-1.17) mmol/l; P < 0.001), and lower-high-density lipoprotein cholesterol (mean +/- 1 SD, 1.26 +/- 0.29 versus 1.35 +/- 0.31 mmol/l). Of these, however, only the difference in very-low-density lipoprotein cholesterol remained statistically significant (P < 0.001) in comparison to age-matched controls. The marked elevation of serum lipoprotein (a) in patients on CAPD may be due to increased hepatic synthesis as a consequence of the substantial amounts of plasma proteins lost in the dialysate. Elevated serum lipoprotein (a) concentrations in CAPD patients may contribute to their risk of coronary artery disease.