A Prospective Evaluation of Clinical Characteristics of Methamphetamine-associated Cardiomyopathy (MACM) in Comparison to a Matched-cohort with Non-methamphetamine Non-ischemic Cardiomyopathy

With globally increasing rates of methamphetamine (MA) abuse, there is a rising prevalence of methamphetamine-associated cardiomyopathy (MACM). The condition, however, is poorly characterized, leaving clinicians with little data to guide diagnosis and management.

To compare clinical characteristics of prospectively encountered patients with MACM to those with non-MA non-ischemic cardiomyopathy (NMACM).

Consecutive patients with MACM confirmed by history presenting to Los Angeles County (LAC)+USC Medical Center between Jun 2018 and March 2020 were interviewed and studied. We retrospectively identified an age- and gender-matched cohort of NMACM and compared demographic, laboratory, and echocardiographic data between the two groups.

140 patients (70 MACM and 70 NMACM) were included. Mean age was similar (49.6±10 vs 48.2±10.5 years, p=0.45) and 94% of patients were male. Patients were predominantly Hispanic in both groups (51% vs 61%, p=0.232) with a greater proportion of Caucasians in the MACM group (21% vs 6%, p=0.007). Significantly more patients with MACM were homeless (47% vs 7%, p=0.001). 20% of MACM patients were college educated. The mean and median duration of MA use prior to a diagnosis of heart failure was 9.8 and 5.5 years, respectively. Two-thirds of MACM patients reported current MA use. MACM compared to NMACM was characterized by lower left ventricular ejection fraction (LVEF) [20% vs 26%, p<0.001], greater LV end diastolic volume (LVEDV) [206mL vs 183mL, p=0.024], and greater LV end systolic volume (LVESV) [161mL vs 134mL, p=0.007]. Right ventricular (RV) dilation was present more often in the MACM group (69% vs 41%, p=0.001) and it was more severe (26% vs 11%, p=0.03). Incidence of intracardiac thrombi was not statistically significant (5.7% vs 2.9%, p=0.403). Frequency of MA use per month did not correlate with greater LVEDV (R²=0.135, p=0.271) or severity of RV systolic function (R²=-0.001, p=0.992). Amount of MA used per week mildly correlated with severity of LVEDV (R²=0.294, p=0.020), but did not correlate with RV systolic function (R²=0.036, p=0.783).

Compared to an age and gender matched cohort of NMACM, prospectively identified patients with MACM had a high incidence of homelessness and significantly more severe myocardial insult with greater degree of LV and RV dilatation and depression of LV function. Frequency or amount of MA use did not appear to be associated with severity of MACM.