Trends and Inpatient Outcomes of Primary Atrial Fibrillation Hospitalizations with Underlying Iron Deficiency Anemia: An Analysis of The National Inpatient Sample Database from 2004-2018

Atrial fibrillation (AF) is the most prevalent arrhythmia in the United States. However, studies evaluating the impact of iron deficiency anemia on AF outcomes are limited. Therefore, we aimed to evaluate the association of iron deficiency anemia (IDA) on clinical outcomes in patients hospitalized with AF. A retrospective analysis of adult hospital discharges from the National Inpatient Sample (NIS) between 2004 and 2018 was conducted. Multivariable logistic regression was used to assess the association of IDA and other clinical outcomes ie inpatient mortality, acute myocardial infarction, cardiogenic shock, acute kidney injury, vasopressors use, length of stay, and other resource utilization. These models were adjusted for patient and hospital-level characteristics. A total of 5,975,241 weighted primary AF hospitalizations were identified. Out of these, 152,059 (2.5 %) had diagnosis of IDA. After adjustment of variables, admissions with IDA were associated with higher rates of acute myocardial infarction (adjusted odds ratio [aOR] = 1.10, 95% CI 1.01-1.19 P= 0.026), use of vasopressors (aOR =1.30, CI 1.27-1.32, P <0.001), invasive mechanical ventilation (aOR = 1.26, CI 1.14-1.40 P <0.001) and acute kidney injury (aOR = 1.72, CI 1.66-1.79 P <0.001). There was no significant difference in all-cause mortality (aOR = 0.97, CI 0.87-1.07, P = 0.513), cardiogenic shock, in-hospital cardiac arrest or use of mechanical circulatory support. Adjusted mortality in patients with AF and IDA decreased from 1.09% to 0.54% from 2004 to2018 (P -trend < 0.001). Among hospitalized patients with AF, our study did not show any difference in all-cause mortality between those with and without IDA.