Objective: Withdrawal of thiopurines after remission is associated with an increased risk of relapse in patients with inflammatory bowel disease (IBD). However, long-term data on thiopurine withdrawal is limited, especially from developing countries where the cost of long-term therapy poses a significant burden on patients.

Methods: Patients with IBD on thiopurine monotherapy for ≥ 4 months, who stopped thiopurines while in clinical remission and were not on any other immunomodulator or biologics at the time of withdrawal, were included in this retrospective analysis.

Results: Among 1093 patients with IBD on thiopurine monotherapy, 461 patients stopped thiopurine due to various reasons. Among these, 218 (ulcerative colitis (UC) = 179; Crohn's disease (CD) = 39) patients were in clinical remission and were continued on mesalamine. Overall, 36.7% (n = 80) relapsed after a median duration of 20 months (IQR: 9-49). Relapse rate was higher in UC than CD (39.7% vs 23%, p = 0.055). Cumulative probabilities of relapse were 17%, 34%, and 44% at the end of 1, 3, and 5 years, respectively. The relapse rate at 5 years was significantly lower in patients who had stopped azathioprine after 4 years of therapy (31% vs 54%, p = 0.007). On multi-variate cox regression analysis, male sex [HR: 1.6(1.0-2.6), p = 0.02] and short duration of therapy with thiopurines [HR: 1.02 (1.01-1.02), p = 0.004] before withdrawal were associated with increased risk of relapse.

Conclusions: Approximately 50% patients with IBD in remission would relapse after 5 years of thiopurine withdrawal. Male sex and shorter treatment duration predict relapse. Treatment should be continued in patients who tolerate and maintain remission on long-term thiopurine.