P731 The impact of thiopurine drugs on the natural history and surgical outcome of ulcerative colitis: A cohort study

Abstract

Thiopurines are used as maintenance therapy in ulcerative colitis, but whether these drugs influence the natural history of the disease is unknown. We aimed to assess the effect of thiopurines in terms of colectomy, hospital admission, progression in disease extent and anti-TNF therapy within 10 years. Patients diagnosed with ulcerative colitis within the Örebro University Hospital catchment area, during 1963–2010 (n = 1007), who initiated thiopurines (n = 253) were included. To overcome the risk of confounding by indication, we used a novel approach and compared patients who stopped treatment within 12 months because of an adverse reaction (n = 76) with patients who continued therapy or discontinued due to other reasons (n = 177). Long-term outcomes were assessed by Cox-regression analyses with adjustments for confounding factors including sex, age, hospital admission at diagnosis, disease extent, and previous medication at first thiopurine exposure. No significant difference in baseline characteristics was observed between the two groups. The cumulative probability of colectomy within 10 years was 19.5% in tolerant patients compared with 29.0% in intolerant, (adjusted HR: 0.43; 95% confidence interval (CI) 0.24 to 0.79; Figure 1). The probability of hospital admission was 34.0 % in tolerant vs. 56.2% in intolerant patients (adjusted HR: 0.38; 95% CI 0.25 to 0.59). The risk for progression in disease extent was 20.4% in tolerant patients compared with 48.8% in intolerant, (adjusted HR: 0.44; 95% CI 0.20 to 0.99). Within 10 years, 16.1% of tolerant and 27.5% of intolerant patients received anti-TNF therapy, (adjusted HR: 0.43; 95% CI 0.24 to 0.79). Figure 1 Based on the novel approach of comparing patients tolerant and intolerant to thiopurines, we, for the first time, reveal that thiopurines have a profound beneficial impact of the natural history and long-term colectomy rates of ulcerative colitis.