[Maintenance therapy by azathioprine after successful treatment by intravenous corticosteroid in acute severe colitis. An open prospective study].

Aims: To investigate the efficacy of azathioprine as maintenance therapy in acute severe colitis of Crohn's disease or ulcerative colitis after successful treatment by intravenous corticosteroids.

Methods: We conduct an open prospective study between 1999 and 2004. All patients with acute severe colitis and good outcome after seven at ten days of intravenous corticosteroid treatment received azathioprine (2-2.5 mg/kg/day). Rates of relapse, severe relapse and recurrence of acute severe colitis were studied and compared to patients treated between 1990 and 1998 with no azathioprine therapy after remission induced by intravenous corticosteroids.

Results: Between 1999 and 2004, 21 patients with acute severe colitis and favourable outcome with intravenous corticosteroid therapy received azathioprine with a mean follow-up of 26 months. Comparatively to the 22 patients with no azathioprine therapy, the rate of relapse was lower in azathioprine group (10% vs 55%; p=0.002) as well as rate of severe relapse (0% vs 36%; p=0.002) and recurrence of acute severe colitis (0% vs 27%; p =0.01). In univariate analysis, predictive factors of relapses were absence of azathioprine therapy (p=0.002 OR [IC95%]: 11.4 [2.12-61.25]), absence of decrease of levels of ESR the 3rd day of treatment (p=0.004 OR [IC95%]: 10.0 [1.79-55.63]) and absence of sigmoid involving (p=0.03 OR [IC95%]: 4.80 [1.15-19.92]). In multivariate analysis, the independent predictive factor of relapse was absence of azathioprine therapy (p=0.003 adjusted OR [IC95%]: 2.17 (1.44-6.66]). The only predictive factor of severe relapse was also absence of azathioprine therapy (p=0.002 OR [IC95%]: 2.5 [1.66-3.84]).

Conclusion: Maintenance therapy with azathioprine is effective in prevention of relapses in patients with acute severe colitis and favourable outcome with intravenous corticosteroid therapy.