Background: The aim of this study was to investigate the predictors of short- and long-term clinical response to the initial anti-TNFs in moderate to severe ulcerative colitis (UC) patients. Methods: A total of 218 UC patients who were treated with infliximab (n=188) or adalimumab (n=30) between December 2006 and November 2016 in Asan Medical Center, Korea (male 60.1%, median age at 41.8 years old [range, 15.85-80.59], and median duration of follow-up 27.2 months [range, 0.9-82.3]) were retrospectively analyzed. Independent predictors of primary non-response (PNR) to anti-TNFs were identified using a logistic regression analysis. Cumulative hazards of poor long-term outcomes (colectomy, anti-TNF failure, and anti-TNF discontinuation) were estimated by the Kaplan-Meier method and were compared between groups divided by predictors using the log rank test. Results: Forty-seven patients (21.6%) showed PNR at week 8. There was no difference between infliximab and adalimumab groups in terms of baseline characteristics. In multivariate analysis, decreased serum albumin W6/W0 ratio (adjusted OR [aOR] 21.89, 95% confidence interval [CI] 6.31-107.78), severe disease (baseline Mayo score ≥ 10) at starting anti-TNFs (aOR 5.86, 95% CI 2.11-17.86), and combined CMV colitis within 3 months (aOR 3.76, 95% CI 1.65-8.96) were significant predictors of PNR. The log rank test revealed no significant differences regarding long-term outcomes between infliximab and adalimumab groups. However, comparison between two cumulative hazard curves regarding long-term outcomes showed significant differences between groups divided by serum albumin W6/W0 ratio cut-off level (1.175 for predicting PNR); anti-TNF failure (p = 0.0002), discontinuation of anti-TNFs (p = 0.016), and colectomy (p = 0.062). Conclusion: Serum albumin week 6/week 0 ratio after initial anti-TNFs is a significant novel predictor of both short- and long-term clinical outcomes in anti-TNF-naïve UC patients.
