OBJECTIVES: To examine correspondences between PROs with changes in disease activity and treatment in patients with UC.  PRO instruments assessed generic health-related quality of life (HRQL; 12-item Short Form v2 [SF-12v2]), disease-specific HRQL (Shortened Inflammatory Bowel Disease Questionnaire [SIBDQ]), and work-related outcomes (WROs; Work Productivity and Activity Impairment Questionnaire: UC [WPAI:UC]).  METHODS: Adults with mild-to-moderate UC received MMX mesalamine 4.8 mg/d for 8 weeks in an open-label, prospective study (NCT01124149).  PROs, and a modified UC-Disease Activity Index (UCDAI) that captured several symptoms, including stool frequency (SF) and rectal bleeding severity (RBS), were administered at baseline and Week 8.  Spearman coefficients examined associations between changes in PROs and disease activity.  Analysis of variance (ANOVA) models tested changes in scores over time, with Cohen’s d’s used to interpret effect sizes.  ANOVAs examined PRO change scores as a function of improvement (≥1-point reduction) in SF and RBS.  RESULTS: