Long-term outcome of patients with Crohn's disease who respond to azathioprine

Background & aims: Little is known about the long-term outcomes of patients with Crohn's disease (CD) who have a complete response to therapy with azathioprine. We assessed the long-term effects of azathioprine in responders.

Methods: We collected data from the MICISTA registry (a database from the Rothschild and Saint-Antoine Hospitals, Paris, France) on consecutive CD patients treated with azathioprine from 1987 to 1999 who responded to therapy (steroid-free clinical remission at 1 y); they were followed up until 2011 (n = 220; 86 men; median age, 32 y; median follow-up period, 12.6 y). Data were compared with those from 440 matched patients with CD who did not receive immunosuppressants during the same inclusion period (controls).

Results: The cumulative rate of sustained remission 10 years after treatment with azathioprine was 38%. Among patients exposed to azathioprine during a prospective follow-up period (1995-2011, 1936 patient-years), the percentage of patient-years with active disease (flare or complication during the calendar year) was 17.6%. Compared with the control group, at baseline, responders were more often active smokers with significantly more extensive disease, perianal lesions, and extradigestive manifestations. During follow-up evaluation, responders had a significantly reduced risk of intestinal surgery (adjusted odds ratio, 0.69; 95% confidence interval, 0.52-0.91) and perianal surgery (adjusted odds ratio, 0.36; 95% confidence interval, 0.27-0.46). A significantly higher percentage of responders developed cancers, including nonmelanoma skin cancers, compared with controls (9.5% vs 4.1%; P < .01). Survival rates after 20 years were 92.8% ± 2.3% of responders vs 97.9% ± 0.8% of controls (P = .01).

Conclusions: Based on a study at a single center, patients with CD who responded to azathioprine had a smaller proportion of patient-years with active disease, and were less likely to be hospitalized or undergo intestinal surgery, than patients with CD who did not receive immunosuppressants. These benefits, however, could be offset by an increased risk of malignancies.