To confirm the hypothesis that thiopurines are better than mesalamine for preventing postoperative recurrence of Crohn's disease (CD) in patients with more than two risk factors.

中文翻译：

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硫嘌呤在预防克罗恩病患者术后复发方面优于美沙拉嗪和两个或多个危险因素

证实硫嘌呤比美沙拉嗪更能预防具有两个以上危险因素的患者的克罗恩病 (CD) 术后复发的假设。