Abstract Background Crohn’s disease (CD) presents with a variable clinical course, and early identification of patients likely to follow a mild trajectory remains a challenge. The PreMiCC score was recently proposed as a predictive tool for mild CD based on five baseline variables. However, external validation is lacking. We aimed to evaluate the applicability and performance of the PreMiCC score in predicting a mild disease course in a tertiary referral cohort. Methods We conducted a single-center retrospective study including CD patients diagnosed between 2004 and 2024. Baseline data (age, CRP, perianal disease, endoscopic severity, and complications) were used to calculate the PreMiCC score. Patients were stratified into ≤2 vs 2 points. Mild disease course was defined by the absence of steroid dependence, immunosuppressive or biologic therapy, and CD-related surgery. Outcomes included need for biologics, CD-related surgery or hospitalization, time to therapeutic escalation, and diagnostic performance of the PreMiCC score. Kaplan–Meier curves, logistic regression, and ROC analysis were performed. Results We included 342 patients (mean age 35±16 years; 52% male) with a mean follow-up of 9±5 years. At diagnosis, 187 patients (55%) had PreMiCC ≤2 and 155 (45%) had PreMiCC 2. Overall, 105 patients (31%) had a mild course, which was more frequent in the PreMiCC ≤2 group (42% vs 17%, p 0.001). Biologic therapy was required in 225 patients (66%), more often in those with PreMiCC 2 (80% vs 54%, p 0.001). CD-related surgery occurred in 63 patients (18%; 17% vs 20%, p = 0.415) and CD-related hospitalisation in 36 (11%; 7% vs 15%, p = 0.023) for PreMiCC ≤2 vs 2, respectively. Patients with PreMiCC 2 had a significantly shorter time to biologic therapy or surgery (log-rank p 0.001). The PreMiCC score showed acceptable performance in predicting a mild course (AUC 0.708). Using the original cutoff 2 yielded a sensitivity of 74%, specificity 55%, positive predictive value 42% and negative predictive value 83% for excluding a mild course; an alternative threshold ≥2 slightly improved sensitivity (83.5%) at the expense of specificity (46.2%). Conclusion This study provides the first external validation of the PreMiCC score and confirms its predictive value in real-world practice. The score reliably stratified patients at diagnosis, accurately identifying those with a mild course and demonstrating a high negative predictive value. Higher scores were associated with earlier therapeutic escalation and increased hospitalizations, reinforcing its relevance for early decision-making. Owing to its simplicity, reproducibility and immediate applicability, this work positions the PreMiCC score as a tool for early risk assessment in CD. References: 1 Kruis W, Bokemeyer B, Jessen P, et al. Prospective Evaluation of the Prediction Score for a Mild Course of Crohn’s Disease (PreMiCC) in Newly Diagnosed Patients With Crohn’s Disease: The PROGNOS Study. Inflamm Bowel Dis. 2025;31(3):677-685. doi:10.1093/ibd/izae086 2 Cho CW, You MW, Oh CH, Lee CK, Moon SK. Long-term Disease Course of Crohn’s Disease: Changes in Disease Location, Phenotype, Activities, and Predictive Factors. Gut Liver. 2022;16(2):157-170. doi:10.5009/gnl210118 3 Rönnblom A, Karlbom U. Clinical course of Crohn’s disease in a population-based cohort in Uppsala County followed for 10 years. Scand J Gastroenterol. 2020;55(11):1301-1307. doi:10.1080/00365521.2020.1829700 Conflict of interest: Dr. Couto Sousa, Diogo: No conflit Fernandes, Samuel Raimundo: None to declare Neves, Andre: No conflt Rodrigues, Inês: No conflit Saraiva, Sofia: No conclit Gonçalves Camilo, Ana Rita: No conflit Valente, Ana Isabel: No conflit Correia, Luis: No conflit
Sousa et al. (Thu,) studied this question.