Diagnosis-Specific Psychiatric Comorbidity in Heart Failure: Associations With Length of Stay, Costs, and Mortality in a National Cohort

Background Psychiatric comorbidities are common in patients hospitalized for heart failure (HF), but diagnosis-specific associations with hospital utilization and outcomes remain unclear, a core question in consultation-liaison (C-L) psychiatry. Objective To evaluate how specific psychiatric comorbidities relate to index length of stay (LOS), hospital costs, and mortality after HF hospitalization. Methods Retrospective cohort study using the 2016–2022 Nationwide Readmissions Database. Adults with a principal HF diagnosis were included. Comorbidities were depression, anxiety, bipolar disorder, schizophrenia/psychotic disorders, post-traumatic stress disorder (PTSD), and substance use disorder (SUD). Outcomes were index LOS, inflation-adjusted costs, and 30-day and 1-year in-hospital mortality during readmissions. Survey-weighted multivariable models adjusted for demographics, socioeconomic factors, hospital characteristics, discharge disposition, and comorbidity burden; p ≤ 0.001 was prespecified. Results Among 31,886,859 weighted HF hospitalizations, psychiatric comorbidity was common. Anxiety was associated with longer LOS (β = 0.88 days; p < 0.001) and higher costs (β=$2,779; p < 0.001) without differences in 30-day or 1-year mortality. Several diagnoses were associated with lower mortality, including depression (30-day OR = 0.86; 1-year OR = 0.86), bipolar disorder (0.66; 0.68), schizophrenia/psychotic disorders (0.68; 0.72), PTSD (0.73; 0.78), and SUD (0.87; 0.92) (all p < 0.001). Bipolar disorder showed the largest cost reduction (β=−$1,320; p < 0.001). Conclusions Psychiatric comorbidity in HF is heterogeneous. Anxiety is associated with increased hospital utilization without a mortality difference, whereas several other diagnoses are associated with lower observed mortality; costs were lower for depression and bipolar disorder. These diagnosis-specific patterns support targeted screening, early consultation, and integrated C-L care pathways during HF hospitalization.