Purpose: Crohn's disease (CD) causes significant economic burden, especially productivity losses.1 Certolizumab pegol, a PEGylated Fc-free Fab’ is effective in CD (PRECiSE trials2, 3). Clinical response (CD Activity Index [CDAI]) was associated with improved health-related quality of life (Inflammatory Bowel Disease Questionnaire [IBDQ]) and increased productivity (Work Productivity and Activity Impairment questionnaire [WPAI:CD]).4 We estimated the smallest changes in WPAI:CD scores in PRECiSE 1 perceived as beneficial by patients/clinicians — minimally important difference (MID). Methods: Using an anchor-based method (relationship between WPAI:CD and independent measures), regressions compared changes in WPAI:CD with those for CDAI and IBDQ between Weeks 0 and 26. Known meaningful changes in CDAI (50 points) and IBDQ (16 points) were used to derive 2 MID estimates. Using a distribution-based method, 3 MID estimates were derived from small (0.2) to moderate (0.5) effect sizes (ES, magnitude of change in WPAI:CD /variability in baseline scores). The 5 MID estimates gave the first MID assessment in WPAI:CD. Results: IBDQ correlated more closely than CDAI with WPAI:CD (Spearman coefficients 0.44–0.65 vs 0.35–0.52); CDAI yielded the lowest MID values. A moderate ES of 0.5 gave outlying values. Mean MID estimates were 6.5% (absenteeism), 6.1% (presenteeism), 7.3% (overall work impairment) and 8.5% (activity impairment) (Table). Conclusion: MID provides a useful benchmark to interpret treatment outcome beyond statistical significance. Changes in WPAI:CD scores >7% can be regarded as sizable changes in workplace productivity. This research was funded by UCB.Table: MID Estimate (%)
No takes yet. Share an insight, caveat, or question.
Sandborn et al. (2007) studied this question.