Disease extent is classified in ulcerative colitis (UC) as E1 (proctitis), E2 (left-sided colitis) or E3 (pancolitis) according to Montreal classification. Extent is one of the major factors that determine disease prognosis over the long-term. Pancolitis is associated with greater medication use, more frequent hospitalizations, and higher rates of surgery, colorectal cancer, and mortality. Disease extension over time in patients with limited disease has also been associated with poor prognosis. A systematic review and meta-analysis were conducted to assess the rate of disease extension in patients with limited UC at diagnosis.Methods:
The PubMed/MEDLINE, Embase, and Scopus databases were systematically searched from their inception through April 2015 to identify epidemiological studies reporting on extension of UC.Results:
Overall, 40 studies were eligible for inclusion but only 28 were included for meta-analysis. The cumulative risk for colonic extension was 18.8% at 5 years and 31.1% at 10 years. Extension was 27% (95% Cl, 24.1–30.2) from E1 to E3, 27.5% (95% Cl, 24.1–31.5) from E2 to E3 and 22.9% (95% Cl, 19.7–26.4) from E2 to E3. Thirteen studies reported information on age at diagnosis with a median of 37.3 years. Rate of extension was significantly higher in patients younger than 37.3 years (27.5%; 95% Cl, 24.5–30.8) than in the older patients (16.8%; 95% Cl, 15.6–18.1) (P < 0.0001). Risk of extension was significantly higher in patients from North America (52%) than in patients from Europe (20.1%) (P < 0.0001).Conclusions:
In this meta-analysis, approximately one fourth of patients with limited UC extend over time with most of extension occurring during the first 10 years. Rate of extension depends on age at diagnosis and geographic origin. Predicting disease extension from diagnosis could lead to personalized therapeutic strategies in patients at risk or not of disease extension.