The relationship among multiple patient-reported outcomes measures for patients with ulcerative colitis receiving treatment with MMX(®) formulated delayed-release mesalamine

PURPOSE: Ulcerative colitis (UC) is associated with impaired health-related quality of life (HRQL) and work-related outcomes (WRO). This analysis examined correspondences among measures of HRQL and WRO in patients with UC, as well as the magnitude of each measure’s responsiveness to disease activity and treatment. METHODS: An open-label, prospective trial of delayed-release mesalamine tablets formulated with MMX(®) technology included 8 weeks of treatment for patients with active mild-to-moderate UC (n = 137) and 12 months of maintenance treatment for patients with quiescent UC (n = 206). Spearman correlations (ρ) measured inter-domain associations across measures of generic HRQL [12-item Short-Form Health Survey (SF-12v2)], disease-specific HRQL [Short Inflammatory Bowel Disease Questionnaire (SIBDQ)], and disease-specific WRO [Work Productivity and Activity Impairment for Specific Health Problems (WPAI:SHP)]. Responsiveness to disease activity and treatment was assessed for each instrument. RESULTS: Changes in scores from baseline to week 8 were moderately correlated across all instrument domains: 65 of 80 (81 %) between-instrument inter-domain correlations were of moderate magnitude (0.30 < ρ < 0.70), with an average magnitude of 0.42 [95 % confidence interval (CI) 0.38–0.46]. Associations between symptom measures were stronger for SIBDQ (|average ρ| = 0.41; 95 % CI 0.34–0.48) and WPAI:SHP (0.40; 0.30–0.47) than SF-12v2 (0.30; 0.27–0.34). SIBDQ was most sensitive to treatment [effect size (d (z)) for change from baseline to week 8 = 0.62; 95 % CI 0.35–0.89], followed by WPAI:SHP (d (z) = 0.43; 0.32–0.54) and SF-12v2 (d (z) = 0.33; 0.27–0.39). CONCLUSION: While the SIBDQ showed the greatest overall responsiveness to disease activity and treatment, all three patient-reported outcomes instruments provided complementary interpretive information regarding the impact of UC treatment.