OBJECTIVES: New e-health technologies can improve patient-physician communication and contribute to optimal patient care. We compared the diagnostic performance of the Simple Clinical Colitis Activity Index (SCCAI) self-administered by patients with ulcerative colitis (UC) at home (through a website) with the in-clinic gastroenterologist-assessed SCCAI. METHODS: Patients were followed-up over 6 months. At months 3 and 6, patients completed the SCCAI online at home; within 48 h, gastroenterologists (blinded to patients' scores) completed the in-clinic SCCAI (reference). SCCAI scores were dichotomized to remission or active disease, and SCCAI changes in disease activity from month 3 to 6 were classed as worsening, stability, or improvement. RESULTS: A total of 199 patients (median age: 38 years; 56% female) contributed with 340 pairs of questionnaires. Correlation of SCCAI scores by patients and physicians was good (Spearman's ρ=0.79), with 85% agreement for remission or activity (95% CI: 80.8-88.6, κ=0.66). The negative predictive value for active disease was 94.5% (91.4-96.6); the positive predictive value was 68.0% (58.8-69.2). Agreement between patient and physician was higher in the 168 month 6 pairs than in the 172 month 3 pairs of questionnaires (89.3% (83.6-93.1) vs. 80.8% (74.2-86.0), P=0.027). CONCLUSIONS: In patients with UC, SCCAI self-administration via an online tool resulted in a high percentage of agreement with evaluation by gastroenterologists, with a remarkably high negative predictive value for disease activity. Remote monitoring of UC patients is possible and might reduce hospital visits.