Myeloperoxidase and C-reactive protein in patients with cocaine-associated chest pain

Background: Myeloperoxidase (MPO) and C-reactive protein (CRP) are markers of inflammation and elevated levels have been found in patients with acute coronary syndrome (ACS) unrelated to cocaine. We evaluated the utility of MPO and CRP for diagnosis of ACS and the prediction of 30-day adverse cardiovascular events in patients with cocaine-related chest pain.

Methods: This is a secondary analysis from a prospective cohort study of ED patients who received evaluation for ACS. Structured data collection at presentation included demographics, chest pain history, laboratory results, and electrocardiographic data. Our primary outcome was diagnosis of ACS at index visit and 30-day adverse events. As a secondary analysis, we provide data on a matched cohort without cocaine use.

Results: Baseline data and CRP were available for 95 cocaine users; 82 had MPO data also. Patients had a mean age of 46.6 (SD 8.1) years, 90% were black, and 62% were male. Acute coronary syndrome occurred in 7% of cocaine users. With respect to diagnosis of ACS, the area under the curve was poor for both MPO (0.65; 95% confidence interval [CI]: 0.40-0.91) and CRP (0.63; 95% CI: 0.39-0.88). Similar results were found for 30-day events. With respect to prognosis of 30-day adverse cardiovascular events, the area under the curve was 0.68 (95% CI: 0.45-0.91) for MPO and 0.67 (95% CI: 0.45-0.90) for CRP. Similar results were found for 30-day events. In the matched cohort of patients who were not cocaine users, performance of MPO (n = 66) and CRP (n = 86) was also poor.

Conclusions: Myeloperoxidase and CRP are not useful for diagnosis or prognosis of patients with cocaine-associated chest pain.