title: Smoking does influence disease behaviour and impacts the need for therapy in Crohn's disease in the biologic era.
abstract: BACKGROUND
  Recently, the notion that smoking may adversely affect Crohn's disease (CD) outcomes has been challenged by the suggestion that the widespread use of immunosuppressants and anti-TNF drugs might offset the adverse effects of tobacco.
  
  
  OBJECTIVE
  To reassess the influence of tobacco smoking on disease phenotype and complications on a time-dependent analysis, taking into account the different therapeutic interventions.
  
  
  METHODS
  We designed a retrospective cohort study of 3224 patients with Crohn's disease. The data were collected from the Spanish national inflammatory bowel disease registry (ENEIDA), including information regarding demographics, clinical characteristics, disease complications, therapeutic interventions and smoking status. Patients were classified as nonsmokers, smokers and former smokers, according to their present and past smoking habits.
  
  
  RESULTS
  In the univariate analysis, smokers had more strictures (22.6% vs. 19.3%, P < 0.05) and less colonic involvement (7.2% vs. 10.9%, P < 0.05), and were more frequently under treatment with steroids (91.6% vs. 85.8%, P < 0.05), immunosuppressants (73.5% vs. 63.6% P < 0.05) or anti-TNF drugs (31.4% vs. 25.1%, P < 0.05) than nonsmokers. In the time-dependent multivariate analysis, smokers were found to have a significantly decreased survival free of stricturing disease (HR: 1.5, CI 95% 1.18-1.90) or perianal complications (HR: 1.50, CI 95% 1.01-1.46), and had a higher risk for requiring thiopurine therapy (HR: 1.20, CI 95% 1.05-1.30).
  
  
  CONCLUSIONS
  These results suggest that, despite the widespread use of immunosuppressants and anti-TNF drugs, smokers with Crohn's disease still have a more severe disease course, with increased therapeutic requirements when compared with nonsmokers.
authors: Hospital Clınic, Barcelona, Spain.
authors: T
authors: T
authors: Nunes
authors: M J
authors: MJ
authors: Etchevers
authors: E
authors: E
authors: Domènech
authors: V
authors: V
authors: García-Sánchez
authors: Y
authors: Y
authors: Ber
authors: M
authors: M
authors: Peñalva
authors: O
authors: O
authors: Merino
authors: P
authors: P
authors: Nos
authors: E
authors: E
authors: Garcia-Planella
authors: A G
authors: AG
authors: Casbas
authors: M
authors: M
authors: Esteve
authors: C
authors: C
authors: Taxonera Samsó
authors: M
authors: M
authors: Montoro Huguet
authors: J P
authors: JP
authors: Gisbert
authors: M D
authors: MD
authors: Martín Arranz
authors: M F
authors: MF
authors: García-Sepulcre
authors: M
authors: M
authors: Barreiro-de Acosta
authors: B
authors: B
authors: Beltrán
authors: N
authors: N
authors: Alcaide Suárez
authors: C
authors: C
authors: Saro Gismera
authors: J L
authors: JL
authors: Cabriada
authors: A
authors: A
authors: Cañas-Ventura
authors: F
authors: F
authors: Gomollón
authors: J
authors: J
authors: Panés
mesh_terms: D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D015331:Cohort Studies; D003424:Crohn Disease / Q000188:drug therapy / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000627:therapeutic use*; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D012306:Risk; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects*; D013030:Spain; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D000893:Anti-Inflammatory Agents; D007155:Immunologic Factors; D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha