Outcomes Among Hospitalized Patients with Amyloidosis and Atrial Fibrillation: A Nationwide Analysis

Background

Amyloidosis can affect virtually any organ system; deposition in the heart usually occurs in primary (AL) and mutated transthyretin (ATTR) subtypes. Clinical presentation ranges from heart failure and infiltrative cardiomyopathy to life threatening ventricular arrythmias. Atrial fibrillation has often been described in literature to manifest in patients with amyloidosis, although its clinical significance needs further exploration.

Methods

We utilized the 2018-2020 National Inpatient Sample (NIS) Database in conducting a retrospective cohort study. We identified hospitalized patients with amyloidosis and atrial fibrillation using appropriate ICD-10 CM codes. We stratified patients based on whether they had atrial fibrillation during the hospitalization or not. A survey multivariable logistic and linear regression analysis was used to calculate adjusted odds ratios (ORs) for the primary and secondary outcomes. A p value of <0.05 was considered statistically significant. The aim of this study is to investigate the outcomes among hospitalized patients with amyloidosis and atrial fibrillation looking primarily at the in-hospital mortality, risk for cardiogenic shock, and hospital length of stay (LOS).

Results

We identified a total of 84604 hospitalized patients with amyloidosis, of which 31.73% (26845/84604) had comorbid atrial fibrillation. The overall in-hospital mortality among those with amyloidosis was 6.42% (5432/84604). Among those who had atrial fibrillation, the overall in-hospital mortality rate was significantly higher at 7.17% (389/5432) (p=0.011). Utilizing a stepwise survey multivariable logistic regression model that adjusted for patient and hospital level confounders, atrial fibrillation among hospitalized patients with amyloidosis did not significantly increase the risk for in-hospital mortality (adjusted OR 1.12, 95% confidence interval [CI], 0.96-1.31; p=0.150) or prolong hospital LOS (p=0.199). However, concomitant atrial fibrillation among hospitalized patients with amyloidosis increased the risk for cardiogenic shock (aOR 1.65, 95% confidence interval [CI], 1.31-2.06; p=<0.001)

Conclusion

Atrial fibrillation continues to be a significant comorbidity in patients with amyloidosis. Our study found a statistically significant increase in the risk for cardiogenic shock, but not for in-patient mortality and hospital LOS. Early identification and prompt management with medical therapy or cardioversion is necessary to prevent disastrous complications. Further prospective cohort studies will help to better assess both short- and long-term outcomes in this patient population.