S892 Impact of Concomitant Hypothyroid Disease and Inflammatory Bowel Disease

Introduction: Inflammatory bowel disease (IBD), comprised of Ulcerative Colitis (UC) and Crohn’s Disease (CD), is caused by a combination of environmental factors, immune dysregulation, and genetic susceptibility. Other immune-mediated phenomena, like hypothyroidism, have also been observed in this population. Thus, we sought to explore clinical characteristics and outcomes among IBD patients with hypothyroidism compared to IBD patients without hypothyroidism. Methods: In a retrospective chart review from a large, tertiary, academic medical center, baseline demographics and clinical data were extracted for patients diagnosed with either UC or CD and having at least one thyroid stimulating hormone (TSH) measurement from prior to 2016. Based on the presence of a documented hypothyroidism ICD-10 code, patients were then divided into two groups, those with IBD alone and those with both IBD and hypothyroidism, as described in Figure. Individual charts were then further examined for disease characteristics, biomarkers, healthcare utilization, medication use, and other comorbidities from 2016 to 2022. Demographic and clinical variables were then compared between the two groups, as seen in Table. Results: We identified 166 adult IBD patients (CD 53%, UC 47%). The mean age was 62.9 years. Among these patients, 116 patients (69.9%) had IBD and hypothyroidism. The most common causes of hypothyroidism were Hashimoto, subclinical, and acquired hypothyroidism. No differences were noted in race, smoking status, or BMI. IBD disease location, behavior, and prevalence of extra-intestinal manifestations did not significantly differ between the two study groups. Both groups had similar number of colonoscopies, hospitalizations, as well as comparable medication use (SSRI/SNRI, steroids, 5-ASA, immunomodulators, biologics). However, patients with IBD and hypothyroidism had higher rates of anemia (p=0.03), hypoalbuminemia (p=0.007), and CRP elevations (p=0.002). Furthermore, patients with both IBD and hypothyroidism had a greater median number of emergency department visits (p=0.039) and axial radiography (p=0.002). Conclusion: IBD patients with hypothyroidism experience a more severe disease course with higher biomarkers of inflammation and healthcare utilization than those without hypothyroidism despite similar IBD phenotype and therapy exposures. This highlights a potential subgroup of IBD patients who may be at risk for increased disease severity and associated poor outcomes.Figure 1.: Flow diagram of retrospective cohort study comparing clinical characteristics and outcomes among IBD patients with hypothyroidism compared to IBD patients without hypothyroidism Table 1. - Baseline characteristics, univariate analysis and multivariate analysis of biomarkers, lab abnormalities, and healthcare utilization Baseline Characteristics at enrollment (Collected prior to 2016) Total Sample IBD only IBD + Thyroid disease P value n 166 50 116 Age, Mean (SD) 62.9 (18.3) 57.8 (19.9) 63.6 (17.3) 0.062 Female (n, %) 118 (71.1%) 30 (60%) 88 (75.9%) 0.039 White 138 41 (82%) 97 (83.6%) 0.798 Never Smoker 95 31 (62%) 64 (55.2%) 0.415 BMI (median, IQR) 25.3 (6.4) 26.0 (8.07) IBD subtype 0.116 CD 87 (52.7%) 31 (62%) 56 (48.7) UC 78 (47.3%) 19 (38%) 59 (51.3%) Disease duration (Years, median, IQR) 7.44 (3.8) 7.68 (4.1) 7.26 (3.6) 0.257 Hypothyroid Disease duration (Years, median, IQR) 7.74 (3.5) Elevated TSH ( >5) ever 55 (33.1%) 5 (10%) 50 (43.1%) < 0.001 Levothyroxine Rx ever 89 (53.9%) 1 (2%) 88 (76.5%) < 0.001 PTU or Methimazole Rx ever 3 (1.8%) 1 (2%) 2 (1.8%) 0.914 Intestinal Surgery ever 61 16 (32%) 45 (39.1%) 0.383 Extra-intestinal disease 19 (11.4%) 3 (6%) 16 (13.8%) 0.148 Univariate Analysis of Biomarkers, lab abnormalities, and Healthcare Utilization during study period (2016-22) Anemia ever 92 (55.8%) 21 (42.9%) 71 (61.2%) 0.03 Hypoalbuminemia ever 39 (23.5%) 5 (10%) 34 (29.3%) 0.007 CRP elevation ever 73 (51%) 12 (30%) 61 (59.2%) 0.002 ESR elevation ever 58 (43.6%) 10 (29.4) 48 (48.5) 0.053 Median # of Colonoscopy 1 (2) 0.5 (2) 1 (3) 0.326 Median # of ED visits 0 (2) 0 (1) 1 (2) 0.039 Median # of Hospitalizations 0 (2) 0 (1) 0.5 (3) 0.101 Median # of Xrays and CT scans 3 (8) 1 (4) 4 (8) 0.002 Multivariate Model of Biomarkers, lab abnormalities, and Healthcare Utilization during study period (2016-22) Adjusted Odds Ratio (95% CI) P-value Anemia ever 2.34 (1.16-4.71) 0.018 Hypoalbuminemia ever 3.82 (1.38-10.56) 0.010 CRP elevation ever 3.19 (1.45-7.03) 0.004 ESR elevation ever 2.21 (0.94-5.15) 0.068 >1 Colonoscopy 1.24 (0.62-2.46) 0.538 >1 ED visit 2.38 (1.17-4.84) 0.016 >1 Hospitalizations 1.59 (0.80-3.18) 0.188 >1 X-rays and CT scans 2.96 (1.43-6.14) 0.003