Clinical outcomes of heart failure in breast cancer patients receiving HER2-directed therapy: A retrospective analysis (2016–2020).

e13003 Background: HER2-directed therapies are a used in the treatment for HER2-positive breast cancer but are associated with cardiotoxicity, including heart failure. Symptomatic heart failure has been reported in a minority of patients receiving HER2-directed regimens. We evaluated inpatient clinical outcomes and healthcare utilization among breast cancer hospitalizations with documented exposure to HER2-directed therapy complicated by heart failure. Methods: We analyzed the National Inpatient Sample (NIS) database (2016–2020). Adult hospitalizations with a primary diagnosis of breast cancer and documented exposure to HER2-directed therapy were identified using ICD-10 codes. Admissions with versus without heart failure (HF) were compared. Categorical and continuous variables were assessed using the chi-square test and Student’s t-test, respectively. Multivariable regression was used to adjust for demographic and clinical confounders and to estimate adjusted odds ratios (aOR). Statistical significance was defined as p < 0.05. Results: A total of 193,684 breast cancer hospitalizations with exposure to HER2-directed therapy were identified; 17,431 had a comorbid diagnosis of HF. Patients with HF were older (mean age 70 years, p < 0.001). Overall, 98% were female and 2% were male (p < 0.001). The cohort was predominantly White (66%), followed by Black (25%) and Hispanic (5%) patients (p = 0.007). HF-associated admissions had a longer mean length of stay (6.5 vs 4.2 days) and higher mean total hospital charges ($65,380 vs $65,278) compared with admissions without HF. In multivariable analyses adjusting for demographics and comorbidities, HF was associated with significantly higher odds of cardiogenic shock (1.3% vs 0.06%; aOR 36; p < 0.001), sepsis (7.4% vs 5.0%; aOR 1.3; p = 0.001), ventricular arrhythmias (3.8% vs 0.7%; aOR 4.5; p < 0.001), and acute hypoxic respiratory failure (29% vs 7.6%; aOR 3.3; p < 0.001). Cardiac arrest was not significantly different after adjustment (0.5% vs 0.3%; aOR 1.1; p = 0.7). Conclusions: Among breast cancer hospitalizations with exposure to HER2-directed therapy, comorbid heart failure was associated with higher inpatient morbidity and healthcare utilization. These findings underscore the importance of risk stratification and proactive cardio-oncology–informed management to potentially reduce complications in this population. In-hospital outcomes and resource utilization among patients with and without heart failure. Outcomes Heart Failure Without Heart failure Adjusted OR P value Length of Stay 6.5 days 4.2 days – – Total Charges 65380 65278 – – Cardiogenic Shock 234/17815 106/175869 36 <0.001 Sepsis 1329/17815 8809/175869 1.3 0.001 Cardiac Arrest 015/17815 560/175869 1.1 0.7 AHRF 5265/17815 13399/175869 3.3 <0.001 Ventricular Arrhythmias 684/17815 1350/175869 4.5 <0.001