2.2. Data collection

The HF database of the Cardiology Division of Metropolitan Hospital Center and the New York City Health and Hospitals Corporation Data Warehouse for Metropolitan Hospital Center was queried for patients with HFrEF who had actively used cocaine and had received β‐blockers as part of their therapy for a period of 12 months. Active cocaine use was defined as either self‐reported continued cocaine use or continued finding of cocaine in the patient's urine during toxicology screening. HFrEF was defined as symptoms consistent with HF and left ventricular ejection fraction (LVEF) <40%, or pro‐brain natriuretic peptide levels >900 pg/mL and LVEF <40%. The subjects' first documented entry of HFrEF was considered as the initial index point for this study.

Forty‐six patients had incomplete follow‐up and were excluded. In addition, 9 patients were excluded due to β‐blocker use prior to the index point, volume overload due to reasons other than HF, presence of chronic kidney disease stage G4 or G5, or life expectancy <12 months.

Demographic information and major cardiovascular comorbidities were obtained. The use of optimal HF medical therapy was documented, as well as type of β‐blocker use. The New York Heart Association (NYHA) functional classification for HFrEF and the LVEF were recorded at baseline and at 12‐month follow‐up. Patients were assumed to be compliant to therapy unless otherwise specified in the electronic medical record. Major adverse cardiovascular events (MACE) was defined as stroke, ACS, or hypertensive urgency/emergency.