MON-440 - Does Hypothyroidism or Hyperthyroidism Impact in-Hospital Mortality in Patients Admitted with Atrial Fibrillation: Insights from the National Inpatient Sample Database.

Background
Atrial fibrillation is one of the most common arrhythmias in hyperthyroidism. However, there is a paucity of data
regarding the association between hypothyroidism and atrial fibrillation. Our objective was to identify whether
hypothyroidism or hyperthyroidism increased complications in patients admitted with atrial fibrillation by utilizing
the National Inpatient Sample (NIS) database.
Methods
We performed a retrospective analysis of the NIS database from 2016 to 2019 using ICD-10-CM codes to
identify patients with atrial fibrillation who had either hypothyroidism or hyperthyroidism. The primary outcome
analyzed was in-hospital mortality; secondary outcomes included length of stay and cost of hospitalization.
Multivariable logistic regression analysis was conducted to compare the in-hospital mortality between these
subsets of patients.
Results
In 674,419 adults with atrial fibrillation also had either hypothyroidism (96.1%) or hypothyroidism (3.9%). The
mean age was 78.1 years ± 10.5 years, and the majority of patients were female (65.8%) and white (86.2%). A
total of 28,307 (4.2%) patients died, and the mortality rate was higher for patients with hypothyroidism 4.24%
vs 3.25%, p < 0.0001. Patients with hyperthyroidism had a higher average hospitalization cost ($63,363 vs.
$61,735, p = 0.0130) and slightly longer lengths of stay (5.7 days vs. 5.6 days, p = 0.0216) compared to
hypothyroidism. Multivariate logistic regression analysis demonstrated hypothyroidism had a higher odds ratio
for in-hospital mortality compared with hyperthyroidism (OR 1.20, 95% CI 1.11-1.30, p < 0.0001). The highest
odds ratio for in-hospital mortality was cardiac arrest (OR 27.38, 95% CI 25.77-29.08, p < 0.0001).
Conclusions
Hypothyroidism is far more common than hyperthyroidism in patients with atrial fibrillation and is associated
with statistically significant higher in-hospital mortality rates. However, acute events such as cardiac arrest or
respiratory failure continue to have higher odds ratios for in-hospital mortality in this patient population. Further
pragmatic research is needed to evaluate how hypothyroidism might contribute to in-hospital mortality in
patients with atrial fibrillation.

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