Ulcerative Colitis and Adverse Outcomes in Hematopoietic Stem Cell Transplantation: A Nationwide Analysis
Authors: Uttam Chandani Kanishka , Agrawal Siddharth pravin , Raval Maharshi , Lotia Dev , Nadeem Ahmed , Kelkar Amar H. 
Published: December 2024

Introduction:
Ulcerative colitis (UC), an inflammatory bowel disease, is characterized by recurrent inflammation and ulceration of the intestinal and colonic tract mucosa with impaired healing mechanisms. This persistent state of inflammation may potentially heighten their risk of complications of allogeneic hematopoietic stem cell transplantation (HCT).
Bone marrow-derived endothelial progenitor cells (BMD-EPC) are thought to play a key role in tissue healing. Murine studies have revealed lower levels of BMD-EPC in mice with UC, which is, thus, associated with poor repair. Additionally, colitis is a key component of acute GVHD in patients undergoing HCT. Our study examines the impact of UC on outcomes in patients undergoing HCT.
Methods:
A retrospective cohort study was conducted utilizing data from the National Inpatient Sample (NIS) for patients undergoing HCT between 2016 to 2021. The cohort was stratified by the presence or absence of UC. Baseline demographics, comorbidities, and outcomes (mortality, bleeding events, blood transfusions, and septic shock) were compared between groups. A multivariable logistic regression model was employed to calculate adjusted odds ratios (aORs) assessing the association of UC with the aforementioned outcomes. Statistical significance was defined as p &lt; 0.05.
Results:
Within the cohort of 139,085 HCT recipients, 610 had a diagnosis of UC. The majority of patients were male (57.3%) and White (67% without UC; 74.1% with UC), but the racial distribution differed between groups, with a higher proportion of Black patients (12.8% without UC; 8.6% with UC) and a lower proportion of Hispanic patients (13% without UC; 11.2% with UC) in the non-UC group. There were relatively similar low proportions of other racial groups including Asians/Pacific Islanders (3.5% without and with UC), Native Americans (0.5% without UC; 0.9% with UC), and other races (3.2% without UC; 1.7% with UC). The highest proportion of patients with UC and without UC undergoing BMT belonged to the highest income quartile at 30.6% and 27%, respectively.
Comorbidities were prevalent in both groups, with diabetes (22.5% without UC; 27.9% with UC) and liver disease (6.02% without UC; 10.66% with UC) more common in the UC group, while dyslipidemia was slightly more common in the non-UC group (25.6% without UC; 24.6% with UC). Notably, patients with UC experienced significantly worse outcomes, including higher cumulative incidence of mortality (4.6% without UC; 10.7% with UC; p=0.001), bleeding events (8.9% without UC; 16.4% with UC; p=0.003), blood transfusions (13% without UC; 19.7% with UC; p=0.03), and septic shock (5.9% without UC; 11.5% with UC; p=0.009).
After adjusting for potential confounders, UC remained independently associated with increased odds of mortality (aOR 2.3, 95% Confidence Interval [CI] 1.2-4.1, p=0.008), bleeding events (aOR 2, 95% CI 1.2-3.3, p=0.005), blood transfusions (aOR 1.7, 95% CI 1-2.7, p=0.03), and septic shock (aOR 1.9, 95% CI 1.1-3.4, p=0.03).
Conclusion:
This nationwide analysis demonstrates that patients with UC undergoing HCT experience significantly higher cumulative incidence of mortality, bleeding events, blood transfusions, and septic shock compared to patients without UC. These findings highlight the importance of recognizing UC as a significant risk factor in this population and emphasize the need for tailored pre-HCT assessment and post-HCT management strategies to mitigate these adverse outcomes.