Crohn's disease: no clear role for olsalazine in maintaining remission

Clinical bottom line (level 1b-)

  1. Patients with ileocaecal or colonic Crohn's disease in remission who received olsalazine compared with placebo were not clearly less likely to relapse, but were more likely to have adverse effects (NNH = 9 at 12 months) , particularly diarrhoea (NNH = 8 at 12 months) .
Mahmud et al: Gut 2001; 49 : 552-556
Expires June 2004

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: 24 acute hospitals, UK, Ireland and France

328 patients (aged mean 39, 54% female) with established Crohn's colitis and/or ileocolitis (confirmed on radiology, histology or endoscopy within 5 years) in complete remssion (CDAI score < 150 for at least 1 month)

Excluded if
  • aged < 18
  • received steroids, azathioprine or other immunosuppresant within 4 weeks
  • concomitant therapy with antibiotics for > 1 month
  • pregnant or planning to be pregnant or breastfeeding
  • clinically significant hepatic or renal insufficiency
  • strictures causing mechanical obstruction
  • fistulae
  • oral or symptomatic anal Crohn's disease
  • stoma or significant small bowel disease apart from terminal ileal disease
  • known hypersensitivity to salicylates

Control Group: (n = 161, 161 analysed): placebo
Experimental Group: (n = 167, 167 analysed): olsalazine increased to a maintenance dose of 2.0 g daily
No other Crohn's disease medication was permitted.
99.7% followed for 12 months

The evidence

Outcome Time to outcome CER EER RRR
(95% CI)		 ARR
(95% CI)		 NNT
(95% CI)
relapse (CDAI > 150) 12 months 42
(26.1%)		 40
(24.0%)		 8%
(-34% to 37%)		 2.13%
(-7.24% to 11.5%)		 47
(NNT = 14 to infinity;
NNH = 9 to infinity)
at least 1 adverse event 12 months 44
(27.3%)		 65
(38.9%)		 -42%
(-95% to -4%)		 -11.6%
(-21.7% to -1.49%)		 -9
(-67 to -5)
diarrhoea 12 months 13
(8.07%)		 35
(21.0%)		 -160%
(-372% to -43%)		 -12.9%
(-20.4% to -5.41%)		 -8
(-18 to -5)

Comments

  1. The study is too small to show any difference between the two groups for the effect of the study drug on relapse.

Citation

  1. Mahmud N, Kamm MA, Dupas JL, et al: olsalazine is not superior to placebo in maintaining remission of inactive Crohn's colitis and ileocolitis: a double-blind, parallel, randomised, multicentre study. Gut 2001; 49 : 552-556
Search Terms:
Contributor: Chris Ball, June 2002
Reviewer:

Clinical Question.
Patient Crohn's disease in remission
Intervention or Exposure olsalazine
Comparison placebo
Outcome relapse, adverse effects