PREALBUMIN AND LIPOPROTEIN(A) IN HEMODIALYSIS - RELATIONSHIPS WITH PATIENT AND VASCULAR ACCESS SURVIVAL

The high morbidity and mortality of hemodialysis patients has led to a search for early markers of risk. Because cardiovascular and nutritional risk are prevalent in this population, we examined the prognostic value of the serum levels of two markers of risk in the general population: (1) lipoprotein(a) [Lp(a)], a low-density lipoprotein-like particle linked to myocardial infarction and coronary bypass stenosis, and (2) prealbumin, a marker of visceral protein status, with a shorter half-life than that of serum albumin. Baseline demographics, clinical information, dialysis prescription, and serum biochemistry measurements of 125 hemodialysis patients followed for up to 14 months were recorded on enrollment. Vascular access events and deaths were recorded prospectively. The hypotheses tested were that increased serum Lp(a) levels would predict cardiovascular mortality and vascular access stenosis and thrombosis, and that reduced serum prealbumin levels would predict mortality risk independently of established risk predictors. Crosssectional analysis of serum Lp(a) demonstrated a skewed distribution with a median value of 38.3 mg/dL (upper tertile, ≥57 mg/dL). Lipoprotein(a) was significantly higher in black patients (P < 0.001) and was significantly correlated (P < 0.005) with total cholesterol and apoprotein B (apoB), but not with a history of prior coronary disease. Serum prealbumin was strongly correlated with serum albumin (r = 0.49, P < 0.001). However, prealbumin correlated (P < 0.001) more strongly with other serum nutrition markers (total cholesterol, apoB, creatinine, urea) than did serum albumin. Fourteen-month cumulative survival was 80%. Age, diabetes, and serum levels of albumin, prealbumin, creatinine, total cholesterol and apoB, but not Lp(a), were correlated with survival in univariate analysis. Using the Cox proportional hazards model, independent predictors of mortality risk were prealbumin less than 15 mg/dL versus higher values (relative risk [RR] = 4.48, P < 0.01), apoB (RR = 0.97 per 1 mg/dL increase, P < 0.02), creatinine less than 10 mg/dL versus higher values (RR = 3.51, P = 0.04), and age (RR = 1.04 per year, P = 0.10). Thirty-eight patients experienced at least one vascular access thrombosis (n = 33) or stenosis (n = 5) during the study. Patients with Lp(a) ≥57 mg/dL had decreased vascular access event-free survival compared with patients with Lp(a) less than 57 mg/ dL (56% v 73%, P < 0.06). This trend was increased in magnitude and statistically significant for white and Hispanic patients (31 % v 79%, P < 0.01). Lipoprotein(a) ≥57 mg/dL was not associated with reduced access event-free survival in black patients (64% v 64%, P = NS). In summary, two serum risk markers, Lp(a) and prealbumin, were evaluated prospectively in 125 hemodialysis patients. Increased serum Lp(a) was found to be a new predictor of vascular access occlusion in white and Hispanic patients. Reduced serum levels of prealbumin, apoB, and creatinine were found to be important independent predictors of mortality risk in hemodialysis patients. © 1993, National Kidney Foundation. All rights reserved. All rights reserved.