Cigarette smoking and appendectomy are risk factors for extraintestinal manifestations in ulcerative colitis

Two common factors, cigarette smoking and appendectomy, have been found to play a role in ulcerative colitis (UC). Data on their role in the development of extraintestinal manifestations (EIM) are scarce.

The relationship between cigarette smoking, appendectomy, and EIM was examined in a prospective study involving 535 (M/F = 319/216) consecutive UC patients followed up for 18 yr. We considered the major EIM: seronegative spondyloarthropathy, pyoderma gangrenosum/erythema nodosum, acute anterior uveitis, and primary sclerosing cholangitis. We excluded patients with a history of EIM or those colectomized before study entry, ex-smokers, and those who started to smoke during the course of UC.

In UC patients, seronegative spondyloarthropathy and dermatologic complications were found increased in smokers (p < 0.0001; p = 0.001) or in subjects with appendectomy (p = 0.0003; p = 0.02), while acute anterior uveitis and primary sclerosing cholangitis did not differ. The Kaplan-Meier analysis showed 18-yr rates for EIM of 71% in smokers and 45% in nonsmokers (log-rank test, p = 0.0001), and of 85% in patients with appendectomy and 48% in those without (p = 0.0001). Cox proportional-hazard model showed that cigarette smoking and appendectomy are independent factors promoting EIM. In smokers with appendectomy the adjusted hazard ratio (3.197, 95% CI 1.529-6.684) was higher than in patients with appendectomy alone (2.617, 95% CI 1.542-4.442) or smoking alone (1.947, 95% CI 1.317-2.879).

In UC patients, appendectomy and cigarette smoking are prognostic factors for the development of EIM. The unfavorable effect of cigarette smoking on EIM is additive to that of appendectomy.