Background: The Mayo score and a noninvasive 9-point partial Mayo score are used as outcome measures for clinical trials assessing therapy for ulcerative colitis (UC). There are limited data assessing what defines a clinically relevant change in these indices. We sought to assess what constitutes a clinically meaningful change in these indices using data from a recently completed placebo-controlled clinical trial.
Methods: In all, 105 patients were enrolled in a 12-week randomized, placebo-controlled trial assessing rosiglitazone for treatment of mild to moderate UC. We compared the change in the Mayo score, the partial Mayo score, and a 6-point score composed just of the stool frequency and bleeding components of the Mayo score to the patient's perception of disease activity at week 0 and week 12. Optimal cutpoints were calculated as the maximal product of sensitivity and specificity.
Results: Each index was strongly correlated with the patient's rating of disease activity at week 12 (Spearman correlations 0.61-0.71, P < 0.0001 for all correlations). The maximal product of sensitivity and specificity to identify patient reported improvement of disease activity was achieved using cutpoints for change of 2.5 for the Mayo score (sensitivity 88%, specificity 80%), 2.5 for the partial Mayo score (sensitivity 88%, specificity 87%), and 1.5 for the 6-point score (sensitivity 88%, specificity 80%).
Conclusions: The partial Mayo score and the 6-point score composed solely of the stool frequency and bleeding components performed as well as the full Mayo score to identify patient perceived clinical response.
Trial registration: ClinicalTrials.gov NCT00065065.