Longitudinal cholesterol trajectories and the risk of relapse in Ulcerative Colitis

초록

Background: Alterations in lipid metabolism have been reported in inflammatory bowel disease (IBD), but the influence of lipid dynamics on ulcerative colitis (UC) relapse remains unclear. This study aimed to investigate whether longitudinal changes in serum cholesterol after clinical remission are associated with relapse in UC patients. Methods: We conducted a retrospective cohort study of UC patients who achieved clinical remission at Samsung Medical Center between 2019 and 2020. Among 491 identified patients, 452 who had at least two lipid measurements during follow-up were included; 199 (44%) experienced relapse (median follow-up duration 67.3 months (95% CI 66–69)). Longitudinal cholesterol trends were compared between relapse and non-relapse groups using a generalized estimating equation (GEE) model. To evaluate time-dependent effects of cholesterol, landmark analyses were performed at 1, 2 and 3 years from the baseline remission. Optimal cut-off values for maximal cholesterol from baseline to each landmark time were determined using the minimum p-value approach based on log-rank tests. Cox proportional hazards regression was applied to estimate hazard ratios (HRs) for relapse beyond each landmark. Results: Cholesterol trajectories differed significantly between relapse and non-relapse groups (interaction effect; p = 0.002). In landmark analyses, higher maximal cholesterol levels were consistently associated with an increased risk of relapse. At the 1-year and 2-year landmarks, patients with maximal cholesterol ≥ 175 mg/dL had a higher risk of relapse (HR 1.73, p = 0.008, and HR 1.88, p = 0.028, respectively). At the 3-year landmark, maintaining maximal cholesterol below 215 mg/dL was associated with significantly fewer relapses (HR 1.92, 95% CI 1.15–3.18, p = 0.012). Conclusion: These findings highlight the potential clinical relevance of lipid monitoring in ulcerative colitis. Regular assessment of serum cholesterol may help identify patients at increased risk of relapse and guide individualized follow-up strategies. Maintaining stable lipid levels during remission could be an important component of long-term disease control, particularly within the first three years after achieving remission.