Factors associated with ulcerative colitis with non-anemic iron deficiency

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BACKGROUND: Non-anemic iron deficiency is common in patients with ulcerative colitis; however, it may be underestimated and untreated, negatively impacting the quality of life. Therefore, this study aimed to investigate factors associated with non-anemic iron deficiency in Japanese patients with ulcerative colitis. METHODS: This cross-sectional study was conducted in Japan between April 2021 and March 2023. The study participants included 112 patients with ulcerative colitis without anemia. Iron deficiency was defined as ferritin levels < 100 and < 30 ng/mL in patients with disease activity (defined as Mayo endoscopic subscores ≥ 2) and those without disease activity, respectively. RESULTS: Patients with ulcerative colitis without anemia were classified as those with iron deficiency (n = 38) and normal iron status (n = 74). The prevalence of non-anemic iron deficiency was 33.9%. Multivariate analysis revealed that female sex (adjusted odds ratio: 15.40, 95% confidence interval: 2.66-89.00) and non-mucosal healing (adjusted odds ratio: 18.10, 95% confidence interval: 2.97-110.00) were independently associated with non-anemic iron deficiency. Conversely, clinical remission, the use of prednisolone, C-reactive protein level, and transferrin saturation level were not significantly associated with non-anemic iron deficiency. CONCLUSION: Female sex and non-mucosal healing were identified as independent factors significantly associated with the prevalence of non-anemic iron deficiency in patients with ulcerative colitis. Therefore, monitoring of iron dynamics in patients with ulcerative colitis who have these characteristics is recommended even in the absence of anemia.