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P365. Smoking and the effect of its cessation on Crohn's disease progression and surgical rates

I. Lawrance1, K. Murray2, B. Batman3, R. Gearry3, R. Grafton4, K. Krishnaprasad5, J. Andrews4, R. Prosser6, P. Bampton6, S. Cooke7, G. Mahy7, G. Radford-Smith8, A. Croft8, K. Hanigan8, 1Centre for Inflammatory Bowel diseases, Fremantle Hospital, University of Western Australia, Fremantle, Australia, 2Centre for Applied Statistics, University of Western Australia, Crawly, Australia, 3Department of Medicine, University of Otago, Christchurch, Christchurch, New Zealand, 4IBD Service, RAH Dept of Gastroenterology & Hepatology and School of Medicine at Royal Adelaide Hospital, Adelaide, SA, Australia, 5Inflammatory Bowel Disease Research Group, Queensland Institute of Medical Research, Brisbane, QLD, Australia, 6Dept of Gastroenterology and Hepatology, Flinders Medical Centre, Adelaide, SA, Australia, 7Gastroenterology, Townsville Hospital, Townsville, QLD, Australia, 8Gastroenterology, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia


Smoking increases the risk of Crohn's disease (CD) and is a prognostic factor under patient control. The aim of this study was to determine if smoking cessation at, prior to, or following, CD diagnosis (Dx) can alter medication use, disease behaviour and need for first or second CD intestinal surgery.


All patients had CD for >5 yrs and data including Montreal classification, smoking history (start/stop date, cigarettes/day), CD-related abdominal surgeries, family history, medication use, disease behaviour at diagnosis (Dx) and follow-up (F/U).


1115 CD patients from 6 centres, with a mean F/U of 16.6yrs, showed that at Dx non-smokers (NS) were more likely to be male (p = 0.047), A1 (p < 0.0001) with L4 (p = 0.028) and perianal (p = 0.03) disease. Disease location (L1, L2 or L3) or behaviour was not different. No differences were seen between smokers' and NS need at some stage in the disease to use oral or iv steroids, or immunosuppression (IS). NS were more likely to receive an anti-TNF agent (p = 0.049). Logistic regression on B1 disease at Dx showed that terminal ileum (TI) CD was more likely to develop into B2/B3 disease (p < 0.0001). Patients continuing to smoke after Dx were more likely than those quitting at Dx to progress to B2/B3 disease (p = 0.017), as were patients who ceased smoking prior to Dx c/w patients who quit at Dx (p = 0.045). B2/B3 disease was more likely if iv steroids (p = 0.004), IS (p < 0.0001) were required or if there was perianal disease (p < 0.0001). 558 patients required intestinal surgery and modelling with smoking status as a predictor showed that smoking was significant (p = 0.044). Multivariate analysis showed surgery was more common with TI (p < 0.0001) and perianal (p = 0.01) disease, while smoking lost significance. 186 patients underwent a 2nd intestinal resection. A greater proportion of smokers underwent a 2nd surgical resection (401%) than patients who quit at, or before, the 1st surgical resection (29%) and NS (28%) but was not significant. There was a general trend in disease behaviour change and the need for 1st and 2nd surgery with increasing numbers of cigarettes/day smoked. Regression analysis identified cigarettes/day smoked as significantly associated with B2/B3 disease change (0.01).


Smoking is a modifiable risk factor. Cessation at Dx reduces the rate of complicated disease as does reducing the number of cigarettes/day smoked. This supports the need for CD patients to be strongly encouraged to cease or at least reduce their smoking.