Higher plasma myeloperoxidase levels are not associated with an increased risk for cardiovascular events in HIV-infected adults

Objectives: Elevated myeloperoxidase (MPO) levels are predictive of high cardiovascular (CV) risk in the general population. The value of MPO as a CV marker in the HIV population has not been investigated. Method: Medical records were reviewed to identify HIV+ patients with a documented CV event (myocardial ischemia/infarction) and stored plasma samples within 1, 2 months prior to the event. HIV+ adults with no CV history and with similarly available stored plasma samples were site-, age-, and gender-matched 1:1 to cases. Results: We identified 124 participants (62 case-control pairs): 94% male, median age 46 years. Median (IQR) MPO levels (pmoles/L) were lower in cases vs. controls: 292 (235-376) vs. 320 (249-467); p = .004. Cases were more likely to have other CV risk factors, including smoking, hypertension, and higher cholesterol and triglycerides. The observed MPO directional difference persisted after controlling for CV risk factors. In the reduced model, observed differences in MPO remained independently and negatively associated with CV event (p = .03) after adjusting for two positively associated risk factors, differences in cholesterol levels (p = .01), and differences in smoking history (ever smoked vs. never smoked; p = .04). Differences in triglycericle levels and hypertension were not statistically significant independent risk factors in this sample (P > .05). Within cases, MPO was negatively correlated with CD4 count (r(s) = -0.40, p = .0023) and age (r(s) = -0.34, p = .01). In contrast, age at blood draw was positively correlated with MPO in controls (r(s); = 0.28, p = .031) and CD4 was uncorrelated (r(s) = -0.01, p >.9). No other factors were significantly correlated with MPO within groups. Conclusion: In contrast to the general population, higher MPO levels were not predictive of CV events in this study, underscoring the fact that pathways operative in HIV arteriopathy may be distinct from traditional CV disease pathogenesis.