ODP371 A Nationwide Analysis of Hospitalization trends of Syndrome of inappropriate anti-diuretic hormone secretion (SIADH) with comorbid Atrial Fibrillation

Syndrome of inappropriate anti-diuretic hormone secretion (SIADH) is a disease of unsuppressed secretion of anti-diuretic hormone (ADH) and its continued action on the Vasopressin (V2) receptors. It is characterized by hyponatremia in a setting of hypervolemia or euvolemia. In this study, we aimed to identify and compare demographic characteristics, adverse outcomes, and complications of SIADH hospitalizations with and without comorbid atrial fibrillation (AF). We analyzed the Nationwide Inpatient Sample (NIS) for 2019 to identify all adult (≥18 years) hospitalizations with a principal diagnosis of SIADH using the ICD-10-CM code (E22.2). Patients <18 years of age were excluded from the analysis. The study cohort was further divided based on the presence of absence of AF. Demographic and hospitalization characteristics were highlighted. Using a multivariate regression analysis adjusting for age, sex, race, primary payer, median household income by zip code, Carlson Comorbidity Index (CCI), hospital location, bed-size, and teaching status, inpatient outcomes such as inpatient mortality, rates of septic shock, acute myocardial infarction (AMI), acute respiratory failure (ARF), acute renal failure (AKI), and acute pulmonary edema (APE) were determined. All p-values< 0. 05 were considered statistically significant. In 2019, of the 39,110 hospitalizations for SIADH, 18.5% of the patients had comorbid AF. SIADH hospitalizations with AF were older (80.4 vs 70.1 years, p<0. 001, predominantly White and a higher proportion of patients with CCI >2 compared to the non-AF cohort. Although there was a higher proportion of females in the AF cohort (61.4% vs 63.1%, p=0.252), we did not find a statistically significant difference for gender between the two subgroups. SIADH hospitalizations with AF were associated with higher adjusted odds ratio (aOR) of inpatient mortality (2.1 vs 0.9%, aOR: 2.45, p<0. 001), increased length of stay (LOS), (5.8 vs 4.8 days, p<0. 001) and increased mean hospitalization cost (THC) ($12,284 vs $10,340, p <0. 001) compared to the non-AF cohort. Furthermore, compared to the non-AF cohort, we noted higher odds of septic shock (0.6 vs 0.3%, aOR: 3.35, p=0. 007) and ARF (11.2 vs 6.5%, aOR: 1.88, p<0. 001) for the AF cohort; however, we did not find a statistically significant difference in the odds of CVA, AKI or AMI between the two groups. Patients hospitalized with SIADH, and comorbid AF had higher inpatient mortality, LOS, THC, which may be secondary to multiple electrolyte abnormalities and fluid imbalances associated with SIADH leading to a worsening of the AF. Furthermore, these patients had higher odds of septic shock and ARF. Hence, it is vital to appropriately manage AF in patients with SIADH to prevent adverse outcomes and decrease the burden on the United States healthcare system. Presentation: No date and time listed