Impact of Inflammatory Disorders on Outcomes in Acute Heart Failure: A Nationwide Analysis

Acute heart failure (AHF) is characterized by rapid symptom deterioration and high mortality. This study evaluates how eight inflammatory disorders, driven by systemic inflammation, immune dysfunction, and antirheumatic cardiotoxicity, impact in-hospital mortality, complications, and length of stay during AHF admissions.

We included patients hospitalized with AHF between 2015 and 18 from the National Inpatient Sample (NIS). The population was compared based on inflammatory disease status. The primary endpoint was in-hospital mortality, with additional endpoints: length of stay and in-hospital complications.

A total of 1,042,218 AHF admissions were included in our analysis, of whom 39,485 were diagnosed with CID. Patients with CID were older (72 vs. 71 years, p < 0.001) and more likely to be female (67.8% vs. 47.0%, p < 0.001). In the adjusted multivariable model, CIDs as a whole were not associated with increased in-hospital mortality (OR: 1.05, 95% CI: 0.98-1.12, p = 0.183) or MACE (OR: 1.00, 95% CI: 0.97-1.05, p = 0.765). However, disease-specific analysis revealed that SLE (OR: 1.56, 95% CI: 1.33-1.85, p < 0.001) and SSc (OR: 1.47, 95% CI: 1.14-1.89, p = 0.003) were independently associated with significantly higher mortality. Additionally, MCTD (9.06 days), SSc (6.50 days), and SLE (6.27 days) patients had significantly longer hospitalizations compared to non-CID patients (5.36 days, p < 0.001). Conversely, a significantly lower risk of major bleeding was observed in Ulcerative Colitis (OR: 0.40, 95% CI: 0.24-0.67, p = 0.001), and Sjögren's (OR: 0.43, 95% CI: 0.26-0.72, p = 0.001) cohorts.

While CIDs as a whole were not found to impact acute heart failure mortality, specific systemic autoimmune rheumatic diseases, namely SLE and SSc, carry a significantly higher risk for in-hospital death. The substantially longer lengths of stay observed in SLE, SSc, and MCTD patients likely reflect severe multi-organ vulnerability and higher resource intensity rather than isolated acute cardiovascular events. Furthermore, the observed reduction in major bleeding risk among specific subgroups suggests that CIDs should not be managed as a monolithic group. Clinicians should remain aware of disease-specific risks when managing AHF in patients with systemic autoimmune conditions.