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Oral 5-aminosalicylic acid for maintaining remission in ulcerative colitis
1Division of Gastroenterology, University of Calgary, Foothills Hospital, 1751 3330 Hospital Drive N W, CALGARY, AB, Canada, T2N 4N1. lsutherl@acs.ucalgary.ca
Objectives:
To assess the efficacy, dose-responsiveness and safety of the newer release formulations of 5-aminosalicylic acid (5-ASA) compared to placebo or sulfasalazine (SASP) in the maintenance of remission in ulcerative colitis.
Search Strategy:
A computer-assisted literature search for relevant studies (1981-1998) was performed using MEDLINE, BIOS, the Cochrane Controlled Trials Register, the Inflammatory Bowel Disease Trials Register, and Science Citation Index, followed by a manual search of reference lists from previously retrieved articles, review articles, symposia proceedings, and abstracts from major gastrointestinal conferences.
Selection Criteria:
Studies were accepted for analysis if they were prospective, randomized, double-blinded, and placebo- or SASP-controlled clinical trials of parallel design with treatment duration of at least six months.
Data Collection And Analysis:
Based on an intention to treat principle, the primary outcome was the failure to maintain clinical or endoscopic remission. Secondary outcomes were the number of patients experiencing adverse events, the number of patients withdrawn due to adverse events, and exclusions or withdrawals after entry into the study (not due to relapse). All data were analyzed using the Peto odds ratio and corresponding 95% confidence intervals (CI).
Main Results:
The Peto odds ratio for the failure to maintain clinical or endoscopic remission (withdrawals and relapses) for 5-ASA versus placebo was 0. 47 (95% CI, 0.36 to 0.62) with an NNT of 6. These values were also calculated for the trials in which SASP and 5-ASA were compared, revealing an odds ratio of 1.29 (95% CI, 1.05 to 1.57), with a negative NNT value (-19), suggesting a higher degree of therapeutic effectiveness for SASP. SASP and 5-ASA had similar adverse event profiles, with odds ratios of 1.16(0.62 to 2.16), and 1.31(0.86 to 1.99), respectively. The NNH values were determined to be 171 and 78 respectively.
Reviewer'S Conclusions:
The newer 5-ASA preparations were superior to placebo in maintenance therapy. However, the newer preparations had a statistically significant therapeutic inferiority relative to SASP.