Addition of mesalazine for subclinical post-surgical endoscopic recurrence of Crohn's disease despite preventive thiopurine therapy: A case-control study

Background and Aim: Thiopurines prevent Crohn's disease (CD) endoscopic recurrence (ER) at least in 50% of patients 1 year after surgery. This study aimed to evaluate the value of adding mesalazine in patients with subclinical ER despite preventive thiopurine therapy. Methods: Crohn's disease patients with ileocecal resection treated with thiopurines for postsurgical recurrence prevention in whom mesalazine was added (cases) to treat ER without clinical recurrence (CR) were identified and compared with those in whom no treatment was added to thiopurines (controls). All patients were followed up for at least 1 year from the index endoscopy. Development of CR as well as evolution of mucosal lesions was evaluated. Results: Thirty-seven patients were included (19 cases and 18 controls). Initial Rutgeerts' score was i2 in 16 patients (9 cases and 7 controls), and i3 in 21 patients (10 cases and 11 controls). After a median clinical follow-up of 59 months (interquartile range 22-100) from the index endoscopy, six cases (32%) and two controls (11%) developed CR (P = 0.2). After a median time to last endoscopic follow-up of 23 months (interquartile range 17-71), 18 patients (49%) showed improvement in Rutgeerts' score, 11 patients (30%) demonstrated progression of mucosal lesions, and 8 (22%) had no changes, with no differences between study groups. Conclusions: The addition of mesalazine seems to be of no benefit in patients with subclinical endoscopic recurrence while on thiopurine prevention. Moderate endoscopic postsurgical recurrence while on thiopurines may even revert with no additional therapy in some patients.