Impact of Psychiatric Comorbidity on Length of Stay and Cost of Hospitalization in Patients With Inflammatory Bowel Disease

Introduction: Patients with Inflammatory bowel disease (IBD) have a higher risk of a psychiatric comorbidity, which increases hospitalization risk and adverse outcomes. However, there remains a paucity of data quantifying the impact of psychiatric comorbidities in patients with IBD on utilization and cost of hospitalization. Methods: This retrospective study analyzed the National Inpatient Sample (NIS) from 2016-2018. Prevalence of psychiatric disorders were compared in hospitalized patients with and without IBD, including anxiety, depression, bipolar, schizophrenia, delusion, psychosis, and personality disorder, and all psychiatric disorders compiled together. The length of stay and total charges were evaluated by multivariable linear regression and adjusted for potential confounders. Results: Among 107,001,355 hospitalizations, 998,055 (63% Crohn’s disease [CD], 37% ulcerative colitis [UC]) involved patients with IBD. 209,615 of the hospitalizations with CD (33.5%), and 102,795 with UC (27.61%) had a comorbid psychiatric diagnosis. CD and UC had an increased risk of a psychiatric disorder (CD: odds ratio [OR] 1.39, 95% confidence interval [CI] 1.37-1.41; UC: 1.14, CI 1.12-1.16), anxiety (CD: 1.56, 1.53-1.58; UC: 1.29, 1.26-1.31), and depression (CD: 1.4, 1.38-1.42; UC: 1.18, 1.15-1.2) compared to hospitalized patients without IBD. Risk of schizophrenia, delusion, psychosis, or personality disorder was not increased. Patients with CD and UC and any psychiatric comorbidity had significantly increased LOS (Table 1). Among patients with IBD and a psychiatric comorbidity, there was no significant increase in total cost. Conclusion: Hospitalized patients with IBD had an increased rate of psychiatric comorbidities, which was associated with significantly increased LOS, but not total cost of hospitalization. Our results demonstrated a modest impact on LOS in patients with anxiety, depression or bipolar disorder and a more significant impact in patients with psychosis, schizophrenia, delusion or personality disorder. The lack of an effect on overall cost of hospitalization is unexpected, though may suggest that patients with IBD and a comorbid psychiatric condition receive fewer costly treatment elements. This study emphasizes the importance of identifying and addressing psychiatric comorbidities in patients with IBD to decrease overall LOS, and highlights the need for further studies exploring inpatient procedures and treatments received within this population. Table 1. - Mean Difference in LOS in Patients with IBD and a Psychiatric Comorbidity PSYCHIATRIC COMORBIDITY CROHN'S DISEASE ULCERATIVE COLITIS MEAN DIFFERENCE 95% CI P MEAN DIFFERENCE 95% CI P ANXIETY 0.325 0.232-0.418 0.000 0.313 0.171-0.455 0.000 DEPRESSION 0.425 0.324-0.526 0.000 0.388 0.223-0.552 0.000 BIPOLAR 0.209 0.004-0.414 0.046 0.450 0.111-0.791 0.010 SCHIZOPHRENIA 2.194 1.524-2.864 0.000 2.744 1.859-3.629 0.000 DELUSION DISORDER 2.850 1.680-4.021 0.000 2.654 1.136-4.171 0.001 PSYCHOSIS 2.567 1.611-3.523 0.000 6.081 3.277-8.886 0.000 PERSONALITY DISORDER 1.828 1.216-2.441 0.000 2.746 1.098-4.394 0.001 ALL 0.603 0.516-0.69 0.000 0.693 0.554-0.832 0.000