Journal Club: Reducing Flare Risk For Smokers!

“The Really Crappy News About Smoking (if you’re a smoker, like I was)”


If you knew me, you’d know that if I were making a blog it would have a research component. I love research, it just makes sense and I’ve learned to really appreciate a well designed thoughtful study. My goal with this is not to convert you into scientists rather I want to try and introduce people to some of the data that your doctors use to help guide your management. I will try to break things down keeping it simple highlighting take home messages of the study showing a figure or two that the authors use to make a point. I am no expert in research I just enjoy it so I may be off in some areas but I’ll do my best, and errors come to light I will make corrections.

I want to begin with a topic that hits home for me, smoking. I started smoking while I was working a summer construction job in the summer of ‘07. Unfortunately it’s no innocuous summer habit and I quickly progressed to buying my own packs. I would estimate I averaged about a half pack a day until about December of 2014. I had two unsuccessful rounds of quitting that both lasted a few months. What always drove me back was I’d get some bad abdominal pain and I would start smoking again (clearly I’m adept at dealing with my problems).My doctors knew/know I smoked and they gave me a begrudging little shrug like you know you should quit and that was the end of it. I think doctors just get tired, the more I learn about this field the more I realize its almost an impossible job.

imagesThere are literally hundreds of journals and thousands of articles out there so I am going to limit our discussions to publications in top tier clinical journals. These journals generally maintain the highest standards for publication (requiring as unbiased analysis as possible and novel data). Be wary of picking sources ‘willy nilly’ from the internet especially if you are considering changing your behavior. It is easy to find quacks out there saying crazy things and they’re usually just trying to sell you things you don’t need. So be careful, read the literature carefully and EDUCATE YOURSELF ABOUT YOUR DISEASE. Anyways, lets get to the study. The citation and link to this article are at the bottom of this post.

Smoking cessation and the course of Crohn’s disease: an intervention study. Gastroenterology 2001

This is a two part study where investigators were interested in 1) Trying to get a high number of patients to quit smoking and then 2) Use a nested case control design to follow those patients who quit for 1 year and then compare the severity of their disease to patients who never smoked and those who continued to smoke. This prospective intervention study coupled with a nested case control series allows the investigators to examine only the variable of interest, smoking cessation.

From 1995-1999 they recruited 899 patients with Crohn’s disease to the prospective study examining interventions to maximize smoking cessation. Some notable findings from this portion of the study were that after intervention (which varied depending on the amount patients smoked-SEE BOTTOM) 12% of the overall patients were able to quit for more than 1 year. Also women taking oral contraceptives and patients who had previous resection (such as myself) were significantly more likely to quit smoking. Okay the natural question that follows is what happened to these long term quitters compared to everyone else? Here is where the beauty of the nested case control study comes to light

There were 59 patients who successfully quit smoking (good for them, trust me it’s a pain in the ass), 59 controls who continued smoking, and 59 control nonsmokers. The groups are purposefully matched for age, gender, duration of disease, and location of their disease. You want the groups you are comparing to be as similar as possible to minimize other factors that may cause active disease which would skew the data. The authors use Kaplan-Meier survival curves to examine the disease course after 1 year of not smoking. Survival curve is really a misnomer and you can think of it more of an “event curve”. In these analyses, each ‘step up’ represents an event being reached by a single patient. For example one patient flared after a specific amount of time so one ‘step’ is added to represent that event.

Kaplan meierFrom the Kaplan Meier curve we can see that patients who quit smoking had disease courses similar to patients who never smoked (the solid dark lines and dashed lines track together). Patients who continued smoking had significantly higher probabilities of flaring, requiring steroids and necessitating increasing immunosuppressive therapy. This study did not find that patients who continued to smoke required more surgery but remember it was only a year of follow up. Had they continued following these patients it is likely that since they flared much more they would have a similarly higher rate of surgery.

Overall, patients who quit smoking had a 65% lower probability of experiencing a disease flare compared to patients who continued smoking. This is an important finding for people with Crohn’s who smoke and it is only possible because of the careful design and execution of this study. Well, I hope you found this little introduction to research interesting a little bit (please do find it interesting). I suspect that people will also be curious about the current research surrounding nutrition, gluten intolerance, new Crohn’s medications in the pipeline and maybe some genetics. You all let me know what topics you are interested in by posting in the comments section and I am happy to go do some digging in pubmed.

Description of intervention:

If you smoked more than 2 cigarettes a day you were given behavioral counseling (lectures about concerning the harms of smoking).If you smoked more than 15 cigarettes you could sign up for a weekly meeting with a physician (an investigator) and if needed they used nicotine patches. They determined smoking cessation based on self report but also performed urinalysis to look for metabolites found in cigarettes.

Cosnes J et al. Smoking cessation and the course of Crohn’s disease: an intervention study. Gastroenterology. 2001 Apr; 120 (5): 1093-9.

PDF of full article on smoking cessation

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