Serum lipoprotein(a) and risk of mortality in patients on peritoneal dialysis

Abstract

Elevated serum lipoprotein(a) [Lp(a)] level is an independent risk factor for atherosclerotic diseases in the general population and hemodialysis patients. However, the association between Lp(a) levels and mortality has received little attention in peritoneal dialysis (PD) patients. The objective of the study was to evaluate the association of Lp(a) levels with all-cause and cardiovascular (CV) mortality in PD patients. This retrospective cohort study was conducted in PD patients enrolled from January 1, 2006 to December 31, 2015, and followed until December 31, 2018. Cox regression models were performed to assess the association of serum Lp(a) levels with all-cause and CV mortality in PD patients. In total, 1492 incident PD patients were eligible for the study. During a median follow-up period of 45.1months, 402 all-cause and 210 CV deaths occurred. Multivariate Cox regression analysis revealed that the first and third tertiles of Lp(a) levels were significantly associated with increased risk for all-cause mortality [hazard ratio (HR)=1.33, 95% confidence interval (95% CI)=1.01-1.75, P=.041; HR=1.53, 95% CI=1.18-1.98, P=.001, respectively] when compared with the second tertile, and the third tertile of Lp(a) level was independently associated with an 80% increased risk of CV mortality (HR=1.80, 95% CI=1.26-2.56, P=.001). Moreover, our results showed that the HRs per log unit higher Lp(a) level for all-cause and CV mortality were 1.53 (95% CI=1.05-2.22, P=.027) and 2.41 (95% CI=1.44-4.03, P<.001), respectively. Our results suggest that both low and high serum Lp(a) levels are risk markers for all-cause death, but only a higher baseline serum Lp(a) level is an independent risk factor for CV mortality in PD patients.