Context: In end-stage renal disease (ESRD), serum high-density lipoprotein cholesterol (HDL-C) level is not an accurate predictor of mortality, partly because it does not necessarily correlate with indices of HDL function. Paraoxonase (PON) is a major enzyme constituent of HDL and key component of HDL antioxidant activity. Apolipoprotein (Apo) A-I is the core HDL structural protein that plays a major role in various aspects of HDL function.

Objective: We sought to examine PON activity and Apo A-I levels in patients with ESRD vs healthy controls.

Design and Setting: PON/Arylesterase activity was measured in 499 patients with maintenance hemodialysis (MHD) and 24 healthy controls with similar distributions of age, sex and race/ethnicity. Serum acrolein-modified Apo A-I was measured in 30 patients with MHD and 10 healthy controls.

Main Outcome Measures: Multilevel Cox models were used to assess associations among PON activity, Apo A-I, and HDL-C levels with 12-month all-cause mortality.

Results: PON activity was significantly lower in patients with MHD vs controls. Furthermore, acrolein-modified Apo A-I levels were higher in patients with MHD vs controls. In fully adjusted models, high PON activity was associated with lower 12-month mortality, whereas no difference of mortality risk was observed across HDL-C levels. The combination of high PON and low Apo A-I compared with low PON and low Apo A-I was associated with lower mortality risk.

Conclusions: In patients with MHD, PON activity had a stronger association with 12-month mortality than HDL-C. Future studies are needed to examine the role of these markers as potential diagnostic and therapeutic tools in ESRD.