Early thiopurine maintenance is associated with reduced proximal disease progression and colectomy rate in ulcerative colitis

BACKGROUND: Thiopurines effectively maintain remission in ulcerative colitis patients. Whether early initiation of thiopurines after ulcerative colitis diagnosis decreases proximal disease progression and colectomy rates is not known. METHODS: We conducted a cohort study of ulcerative colitis subjects recruited from 1970 to 2009. Early thiopurine maintenance was defined as commencement of azathioprine or mercaptopurine within 5 years of diagnosis and maintenance for at least 6 months. Propensity score matching was conducted to correct for confounders influencing early thiopurine introduction. Outcomes of interest were colectomy rate and endoscopic proximal disease extension. RESULTS: 982 consecutive ulcerative colitis subjects (12 879 patient-years) were recruited with 116 requiring colectomy. Thiopurines initiation and maintenance increased over time with median time to thiopurine commencement decreasing from 23 years in the first decade to 2 years in the last decade (P < 0.0001). Multivariate analysis showed that early thiopurine maintenance significantly decreased the need for colectomy [hazard ratio, 0.13; 95% confidence interval (CI):0.03-0.55; P = 0.006]. The number of subjects needed to be treated to reduce one colectomy at 5 and 10 years was 18 (95% CI, 16- 36) and 12 (95% CI, 11-25). After propensity score matching, early thiopurine maintenance was significantly associated with decreased colectomy (hazard ratio, 0.10; 95% CI, 0.03-0.43; P = 0.002) and proximal progression of disease extent (hazard ratio, 0.26; 95% CI, 0.10-0.78; P = 0.015). CONCLUSION: Early thiopurine maintenance for >6 months is significantly associated with reduced colectomy and proximal progression of disease extent in ulcerative colitis.