Aims: Methadone poisoning/overdose is an international public health problem. We aimed to determine if methadone poisoning increased cardiac troponin and if troponin levels predicted the need for ICU admission, intubation, and mortality in methadone-poisoned patients.

Methods: In an observational prospective single-center study, all eligible patients (age >14 years) admitted with the diagnosis of single-drug exposure of methadone were included. Two-hundred and ninety-nine patients were initially enrolled, of whom 54 patients were excluded, since they had co-existing conditions that were considered a probable cause of elevated troponin I. An electrocardiogram and troponin I were obtained on ED presentation for each patient. Patients were followed for need for intubation, ICU admission, and in-hospital mortality.

Results: Of 245 included patients, 186 (75.9%) were males. The median age was 33 years. Nineteen (7.7%) patients had troponin I levels of > 0.1 ng/mL (positive), and 41 (16.7%) had borderline levels of 0.019-0.1 ng/mL. Twenty-three (9.3%) cases were admitted to the ICU, 21 (8.5%) needed intubation, and five (2%) died during hospitalization. ROC curve analysis showed that positive troponin with a 0.0365 ng/mL cut-off value had a significant association with mortality (OR=23.4; 95% CI 2.5, 215.8; p=0.002).

Conclusions: Methadone exposure/toxicity is a newly identified cause of elevated troponin I. A troponin I cut-off value of 0.0365 ng/mL predicted mortality in our sample and requires validation internationally. Future studies should measure troponin levels in methadone maintenance treatment clients in longitudinally to assess possible evidence of myocardial injury from long-term exposure.

Presentation slides: Troponin: A predictor of mortality in methadone exposure – An observational prospective study