Appendectomy reduces the risk of having ulcerative colitis (UC), however, its effect on the natural history of UC remains uncertain.
In this study, a team of researchers from France sought to determine whether appendectomy reduces the overall severity of UC.
They assessed 638 consecutive patients between 1997 and 2000.
|10-year risk of colectomy:|
- appendectomized = 16%
- non-appendectomized = 33%
The team determined appendectomy status and smoking habits by direct interview.
In addition they assessed severity of UC by reviewing therapeutic needs from the onset of colitis.
Furthermore, the team prospectively assessed the annual incidence of flare up, between 1997 and 2000, in patients who had not been colectomized.
The research team found that the 10-year risk of colectomy was 16% in 49 previously appendectomized patients, compared with 33% in 589 non-appendectomized patients.
Cox regression showed that previous appendectomy and current smoking were independent factors protecting against colectomy (adjusted hazard ratio, 0.40 and 0.60, respectively).
The team determined that respective proportions of appendectomized and non-appendectomized patients, who required oral steroids and immunosuppressive therapy were not significantly different (67% versus 70% and 27% versus 19%, respectively).
Between 1997 and 2000, UC was active for 48% of the time in appendectomized patients and for 62% of the time in non-appendectomized patients.
Prof. Cosnes's team concluded, "Previous appendectomy is associated with a less severe course of UC".
"The beneficial effect of appendectomy on the risk of colectomy is additive to that of current smoking".
Further to the previous study, researchers in Australia have compared appendectomy rates in inflammatory bowel disease patients, and evaluated the effect on disease characteristics.
Their study is also published in the latest issue of Gut.
The research team identified study subjects from the Brisbane Inflammatory Bowel Disease database, and matched controls from the Australian Twin Registry.
They collected data on age at diagnosis, disease site, need for immunosuppression, and intestinal resection.
The research team confirmed the negative association between appendectomy and UC (odds ratio, 0.23), and also found a similar result for Crohn's disease, once the bias of appendectomy at diagnosis was addressed (OR, 0.34).
In addition, they determined that prior appendectomy delayed age of presentation for both diseases. This was statistically significant for Crohn's disease.
Furthermore, in UC, patients with prior appendectomy had clinically milder disease with reduced requirement for immunosuppression (OR 0.15) and proctocolectomy.
Dr Radford-Smith's team concluded, "Compared with patients without prior appendectomy, appendectomy before diagnosis delays disease onset in UC and Crohn's disease and gives rise to a milder disease phenotype in UC".