How effective are current drugs for Crohn's disease? A meta-analysis.

We have conducted a meta-analysis of 12 placebo controlled trials to determine the efficacy of single drug therapy in Crohn's disease for both induction (seven trials) and maintenance (five trials) of remission. A total of 767 and 796 patients were studied, respectively. Various clinical criteria of success were analyzed. The Dersimonian-Laird method for meta-analysis was used to calculate the risk difference (RD). Therapeutic advantage, defined as the difference between drug and placebo response, was also determined. Using various criteria of success, we found that single drug therapy conferred an 11-29% therapeutic advantage (RD = 0.13-0.33) over placebo for the induction of remission. In trials for maintenance, no therapeutic advantage was found for single drug therapy over placebo. All forms of maintenance therapy followed nearly identical linear rates of relapse over time, showing an approximately 90% maintenance of remission rate at 3 months, which decreased to 25% at 36 months. In conclusion, meta-analysis has established a standard of reference against which future drug trials can be compared. This standard of reference for drug and placebo rates, as well as the corresponding risk differences and therapeutic advantages can help determine the relative value of newer agents in the therapy of Crohn's disease.