Decreased Serum Antibodies Against Oxidized Low-Density Lipoprotein Levels Are Associated with Peripheral Arterial Disease in Patients Undergoing Peritoneal Dialysis

Background and Objectives: Peripheral arterial disease (PAD) is highly prevalent in patients with end-stage renal disease and is associated with adverse cardiovascular outcomes. Although the ankle–brachial index (ABI) is widely used to identify PAD, it may not fully reflect the complex vascular pathophysiology in patients undergoing peritoneal dialysis (PD). Antibodies against oxidized low-density lipoprotein (anti-oxLDL Ab) have been implicated in atherogenesis; however, their clinical relevance in PD populations remains unclear. Materials and Methods: In this cross-sectional investigation, 90 patients receiving maintenance PD were included. PAD was defined by an ABI below 0.90, and serum anti-oxLDL antibody concentrations were quantified using an enzyme-linked immunosorbent assay. Results: Patients with PAD were older (p = 0.006), had a higher prevalence of diabetes (p = 0.010), and exhibited higher levels of triglycerides (p = 0.008), fasting glucose (p < 0.001), and C-reactive protein (CRP, p < 0.001), but lower anti-oxLDL Ab levels (p = 0.008). Multivariable logistic regression demonstrated that reduced anti-oxLDL Ab levels (per 10 mU/mL increase, odds ratio [OR]: 0.803, 95% confidence interval [CI]: 0.648–0.995, p = 0.045) and increased CRP levels (per 0.1 mg/dL increase, OR: 1.662, 95% CI: 1.152–2.398, p = 0.007) were independently associated with PAD, with consistent results across penalized regression models. Log-transformed anti-oxLDL Ab levels were positively correlated with both left and right ABI values (p = 0.005 and p = 0.017, respectively). Decision curve analysis indicated that the anti-oxLDL Ab-based model provided greater net benefit compared with the treat-all and treat-none strategies across a range of threshold probabilities. Conclusions: Reduced serum anti-oxLDL Ab levels are independently associated with PAD in patients undergoing PD. Serum anti-oxLDL Ab levels are positively associated with ABI values. These findings suggest that impaired immunity against oxidized LDL may contribute to vascular disease in PD patients.