Association of Iron Deficiency Anemia with Outcomes in Atrial Fibrillation: A Nationwide Analysis

Patients with atrial fibrillation (AF) frequently have iron deficiency anemia (IDA), but the mechanism by which this condition affects clinical outcomes is not well understood. The purpose of this study was to assess whether IDA is associated with mortality in patients with AF. Data from the National Inpatient Sample (NIS) for 2021-2022 examined IDA and inpatient outcomes in a nationally representative cohort of hospitalized adults diagnosed with AF. Patients were categorized by IDA status. The factors assessed were mortality, hospital and intensive care unit (ICU) length of stay, thromboembolic and cardiovascular complications, and overall hospital expenses. Hospital, clinical, and demographic factors were included in multivariable logistic and linear regression models. Of the 8.35 million AF hospitalizations, 7.1% had associated IDA. IDA was linked to multiple comorbidities along with increased risk of hypotension (OR: 1.15, 95% CI 1.12-1.17, P<0.001), acute kidney injury (OR: 1.25, 95% CI 1.23-1.27, P<0.001), and heart failure (Adjusted Odds Ratio [AOR]: 1.29, 95% CI 1.27-1.31, P<0.001). Ironically, IDA was linked independently to decreased risks of cardiac arrest (AOR: 0.70, 95% CI 0.66-0.73, P<0.001), transient ischemic attack (AOR: 0.58, 95% CI 0.53-0.63, P<0.001), stroke (OR: 0.49,95% CI 0.47-0.51, P<0.001), and in-hospital mortality (OR: 0.66, 95% CI 0.64-0.68, P<0.001). IDA was also associated with increased hospital expenses and increased LOS (P<0.001). IDA was linked to higher morbidity and healthcare use in those with AF admitted to the hospital, but there was a decrease in mortality and thromboembolic events. These results suggest the possibility of tailored iron therapy and imply a complex interaction between IDA and AF-related outcomes.