In the Journals

Smoking linked to worse Crohn’s disease, need for more therapies

Patients with Crohn’s disease who were current or former smokers had more severe disease and required more treatments than nonsmokers in a recent retrospective cohort study.

Researchers evaluated 3,224 patients with Crohn’s disease (CD) enrolled in the Spanish national IBD registry. Patients were divided into subgroups according to their smoking habits: nonsmokers (never smokers or those who stopped smoking more than 12 months before CD diagnosis; n=1,689), smokers (n=1,081) and former smokers (smokers who had quit within 12 months of CD diagnosis; n=454). Analysis according to previous tobacco exposure also was performed, with 1,689 patients classified as nonsmokers and 1,535 as tobacco-exposed.

Smokers were significantly more likely than nonsmokers to have strictures (22.6% compared with 19.3%) and receive therapy with steroids (91.6% vs. 85.8%), immunosuppressants (73.5% vs. 63.6%) or anti-TNF drugs (31.4% vs. 25.1%). Smokers also were significantly less likely to have colonic IBD involvement (7.2% of patients vs. 10.9%). Investigators said former smokers had significantly higher steroid, immunosuppressant and anti-TNF usage than the other groups; inflammatory disease phenotype and penetrating disease complications also were more frequent among former smokers (P<.05 for all comparisons).

Tobacco-exposed participants had significantly less colonic disease and inflammatory disease behavior, and significantly more perianal disease and stricturing, compared with nonsmokers. Steroid, immunosuppressant and biologic use were all more common among patients exposed to tobacco (P<.05 for all).

When smoking was analyzed as a time-dependent variable, with patients identified as active smokers or nonsmokers, multivariate analysis indicated significant associations between smoking and reduced survival time without strictures (HR=1.5; 95% CI, 1.18-1.9) or perianal complications (HR=1.21; 95% CI, 1.01-1.46), as well as a significantly increased risk for requiring thiopurine therapy (HR=1.2; 95% CI, 1.05-1.3).

“In the largest cohort study to date, we have found that smokers continue to have worse disease outcomes when compared with nonsmokers,” the researchers concluded. “This group also has earlier and more prevalent requirements of immunosuppressants and anti-TNF therapy, suggesting the presence of an increased disease activity among smokers.”

Disclosure: The researchers report no relevant financial disclosures.