TWO DECADES OF INCREASING IBD MORTALITY LINKED TO PSYCHIATRIC COMORBIDITIES IN THE UNITED STATES

Abstract BACKGROUND Inflammatory bowel disease (IBD), encompassing Crohn’s disease and ulcerative colitis, is increasingly recognized as a systemic illness with psychiatric comorbidities that may affect disease course and outcomes. However, national mortality trends where mental and behavioral disorders (MBD) contribute to IBD deaths remain poorly characterized. METHODS We analyzed U.S. mortality data from the CDC WONDER Multiple Cause of Death database (1999–2020). Deaths were included if IBD was the underlying cause and an MBD diagnosis was listed as a contributing cause. Annual age-standardized mortality rates (per 100,000 population) were calculated, and temporal trends were examined using log-linear regression to estimate annual percent change (APC) with 95% confidence intervals (CIs). Subgroup analyses were performed by census region, 2013 urbanization, 10-year age groups, sex, race, and Hispanic origin. RESULTS From 1999–2020, 2,051 deaths were attributed to IBD with MBD as a contributing cause. The crude mortality rate rose from 0.017 per 100,000 in 1999 to 0.045 per 100,000 in 2020, reflecting a significant overall increase (APC +4.43%, 95% CI 3.52–5.35; p < 0.001). Increases were observed across all census regions, highest in the South (+5.54%) and Midwest (+4.65%). By urbanization, the steepest rise occurred in medium metro areas (+5.45%). Age-specific APCs were positive across all groups, peaking among 25–34 years (+7.35%), 35–44 years (+6.80%), and 45–54 years (+6.57%), with smaller increases in older adults (≥85 years: +1.51%). By sex, mortality rose significantly in males (+5.66%) and females (+3.88%). Racially, White individuals (+4.45%) and non-Hispanic populations (+4.77%) showed significant increases; other categories were suppressed due to small counts. CONCLUSION Mortality in which IBD was the underlying cause and MBD a contributing cause more than doubled in rate over two decades in the U.S. The steepest increases occurred among younger adults, males, and residents of the South and medium metro areas. These findings underscore the importance of integrating psychiatric evaluation and management into IBD care and highlight the need for targeted interventions to address high-risk populations.