S442 Constipation in Atrial Fibrillation and Atrial Flutter Admissions: A Hidden Driver of Mortality and Adverse Outcomes

Introduction: Constipation, in hospitalized patients, often contributes to altered electrolyte homeostasis and vagal tone—2 factors with significant implications in cardiac rhythm regulation. Atrial fibrillation and flutter (AF/AFL) are among the most frequent arrhythmias requiring hospitalization, and yet the influence of constipation on AF/AFL outcomes remains poorly explored. This study aims to investigate whether constipation is independently associated with worse in-hospital outcomes in AF/AFL admissions. Methods: We conducted a retrospective cohort analysis using the 2021 National Inpatient Sample (NIS), which approximates a 20% stratified sample of all U.S. hospital discharges. Patients admitted with a primary diagnosis of AF or AFL were identified using ICD-10-CM codes, and comorbid constipation was determined using secondary codes. Multivariable logistic regression was used to assess associations with inpatient mortality, adjusting for demographics and comorbidities. Fisher’s exact test and linear regression were employed to analyze categorical and continuous outcomes, respectively. STATA version 18.5 was used for all statistical analyses. Results: Among 442,909 weighted AF/AFL admissions, 15,404 (3.5%) had comorbid constipation. These patients were older (75.0 vs 71.1 years, P < 0.005), more likely to be female (56.3% vs 47.8%, P < 0.005), and had higher rates of depression (13.2% vs 9.1%, P < 0.005), hypothyroidism (P = 0.006), and opioid use disorder (P < 0.005). The mean Charlson Comorbidity Index was higher in the constipation cohort (2.81 vs 2.17, P < 0.005). Constipation was associated with increased hospitalization costs ($74,777 vs $60,998, P < 0.005) and length of stay (5.59 vs 3.23 days, P < 0.005; β = 2.07, 95% CI 1.83–2.31). After adjustment, constipation remained significantly associated with in-hospital mortality (adjusted odds ratio [aOR] 1.35, 95% confidence interval [CI] 1.03–1.05, P = 0.037), with a stronger effect seen in patients under 65 years (aOR 2.00, 95% CI 1.05–3.81, P = 0.034), but not in those over 65 (P = 0.132). Conclusion: Constipation in AF/AFL admissions is independently associated with increased mortality, longer hospitalization, and higher comorbidity burden. These findings are particularly significant in patients under 65, suggesting the need for early recognition and management of constipation as a potentially modifiable risk factor. Further prospective studies and randomized trials are warranted to determine whether laxative use can improve cardiovascular outcomes in this population.