Clinical outcomes of anemia in patients with spontaneous coronary artery dissection: a retrospective cohort analysis

Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndrome, especially in younger patients and women. Anemia, a common comorbidity in patients with cardiovascular disease, may modulate outcomes in SCAD, but its influence remains poorly defined. We identified adult hospitalizations for SCAD in the Nationwide Inpatient Sample (2016–2022), stratified by anemia status. Multivariable logistic regression models were constructed to examine the relationship between anemia and in-hospital outcomes, while adjusting for demographics, comorbidities, and hospital characteristics. The primary outcome was all-cause in-hospital mortality. Secondary outcomes included cardiac arrest (CA), mechanical circulatory support (MCS), cardiogenic shock (CS), heart failure reduced ejection fraction (HFrEF), heart failure preserved ejection fraction (HFpEF), blood transfusion (BT), vasopressor use (VU), mechanical ventilation (MV), acute kidney injury (AKI), atrial fibrillation (AF), length of stay (LOS) and total hospital charges (THC). Among 63,450 SCAD hospitalizations, 24.8% had comorbid anemia. Patients with anemia were older (63.4 vs. 59.7 years) and had a higher comorbidity burden. While no significant difference in in-hospital mortality was observed (10.8% vs. 4.6%; adjusted odds ratio [aOR] 1.15, 95% confidence interval [CI]: 0.96–1.38; p = 0.115), anemia was associated with significantly greater odds of MCS (28.2% vs. 9.5%; aOR 2.64, CI: 2.34–2.99; p < 0.001), CS (23.5% vs. 6.9%; aOR 2.27, CI: 1.98–2.61; p < 0.001), HFrEF (20.7% vs. 12.1%; aOR 0.99, CI: 0.88–1.14; p = 0.324), HFpEF (8.8% vs. 4.3%; aOR 1.26, CI: 1.04–1.52; p = 0.020), VU (9.3% vs. 2.1%; aOR 2.56, CI: 2.04–3.20; p < 0.001) AKI (33.2% vs. 9.5%; aOR 2.28, CI: 2.02–2.59; p < 0.001) AF (27.0% vs. 12.9%; aOR 1.74, CI: 1.55–1.97; p < 0.001) BT (17.8% vs. 1.3%; aOR 12.71, CI: 10.07–16.04; p < 0.001). Anemia was associated with increased hospital length of stay (LOS) (10 vs. 4 days; β = 3.9; p < 0.001) and higher THC ($285,660 vs. $114,861; β = $117,902; p < 0.001). Among patients hospitalized with SCAD, anemia was associated with higher risks of hemodynamic compromise, acute kidney injury, atrial fibrillation, and greater resource utilization, although mortality differences were not statistically significant. Recognition of anemia may help identify high-risk SCAD patients needing closer monitoring and tailored management.