Abstract INTRODUCTION Several risk factors have been associated with inflammatory bowel diseases (IBD), including genetic, environmental, gut microbiota and immune dysregulation. Psychiatric disorders have been linked to IBD. However, the question of whether psychiatric conditions affect the severity of patients with IBD remains unanswered. We aimed to investigate the relationship between mood disorders and IBD outcomes. METHODS This is a retrospective longitudinal study of patients admitted with a primary diagnosis of IBD. Data was retrieved from the Nationwide Inpatient Sample (NIS) databases of the years 2016 to 2019 using ICD-10-CM codes for IBD. Multivariate logistic regression analysis was applied to estimate the effect of mood disorders on the outcomes of IBD (mortality, complications and hospital utilization), while adjusting for patient and hospital confounders. A T-Test and Chi Square test were performed to compare baseline characteristics in patients admitted for IBD with and without a secondary diagnosis of mood disorder (table 1). We used Stata® Version 17.0 Software (Statacorp, Texas, USA) for analysis. The p-value was set at p < 0.05. RESULTS A total of 374745 adults with a primary diagnosis of IBD were identified; less than one fifth (21%) had a documented mood disorder. A significantly higher proportion of females (66%, p-value=0.000) and Whites (81%, p-value=0.000) were noted in the mood disorder group. Having a mood disorder was associated with no statistically significant change in mortality (Odds ratio (OR) = 0.86, p = 0.461), anemia (OR = 0.99; p = 0.891), gastrointestinal bleed (OR = 0.99; p = 0.910), inflammatory polyps (OR = 0.79; p = 0.452), toxic megacolon (OR = 0.79; p = 0.664), colorectal cancer (OR = 0.70; p = 0.133), primary sclerosing cholangitis (OR = 1.34; p = 0.228), and pyoderma gangrenosum (OR = 1.01; p = 0.945) (figure 1). A statistically but non clinically significant reduction in the risk of intestinal abscess (OR= 0.81; p = 0.024), stenosis (OR= 0.68; p = 0.000), and fistula (OR= 0.84; p =0.012), was noted in patients with mood disorder. However, an increased hospital utilization was noted in patients with mood disorder (length of stay: 0.59 days, p-value = 0.000; total healthcare cost: 3372 US Dollars, p-value = 0.000). DISCUSSION IBD patients demonstrate a higher prevalence of mood disorders when compared to the general population, especially in females and Whites. Our study showed that the presence of mood disorder concurrently with IBD does not significantly affect the outcomes of IBD in terms of mortality, or morbidity. A multidisciplinary approach of patients with IBD including diagnosis and management of the underlying psychiatric disorders could help optimize the hospital utilization of patients with IBD.