Smoking Not Beneficial for Patients with Ulcerative Colitis

August 09, 2019
Despite contradictory previous research, investigators warn ulcerative colitis (UC) patients not to reach for a cigarette.

A team, led by Jonathan Blackwell, BMBS, of St. George's Healthcare NHS Trust and St. George's University, in London, used a nationally representative clinical research database and grouped 6754 patients 3 groups—never smoked, ex-smokers, and smokers—to identify incident cases of UC between 2005-2016 with a cumulative 41,025 person years of follow-up.

They then created different subgroups, including persistent smokers and smokers who quit within 2 years after being diagnosed with UC and compared the rates of overall corticosteroid use, corticosteroid-requiring flares, corticosteroid dependency, thiopurine use, hospitalization, and colectomy between the different groups.

Of the 6754 patients in the study, 878 were considered smokers when diagnosed with UC, 3178 were ex-smokers, and 2698 were never-smokers.

The follow‐up time was longer for never‐smokers compared with ex‐smokers and smokers (5.2, 4.9 and 4.8 years, P < .05). Also, 46% of patients who were smokers at the time of diagnosis continued to smoke, while just 2% of never smokers took up the habit after they were diagnosed.

The investigators found that smokers had a similar risk of corticosteroid-requiring flares (OR 1.16, 95% CI .92‐1.25), thiopurine use (HR .84, 95% CI .62‐1.14), corticosteroid dependency (HR 0.85, 95% CI .60‐1.11), hospitalization (HR 0.92, 95% CI .72‐1.18), and colectomy (HR .78, 95% CI .50‐1.21) to the group that had never smoked.

Also, rates of flares, thiopurine use, corticosteroid dependency, hospitalization, and colectomy were not substantially different between persistent smokers and participants who give up smoking following their UC diagnosis.

“Smokers and never‐smokers with UC have similar outcomes with respect to flares, thiopurine use, corticosteroid dependency, hospitalization, and colectomy,” the authors wrote. “Smoking cessation was not associated with worse disease course. The risks associated with smoking outweigh any benefits.”

Patients were excluded from the study if they had a co-morbid condition that could require regular or prolonged corticosteroid use, including chronic asthma, polymyalgia rheumatic, and organ transplants.

Using data on hospitalization, ex-smokers were less likely to have an irritable bowel disease-related hospital admission than either smokers or never-smokers (22.6% vs 27.8% vs 25.8% respectively, P = .017).

They also broke down the participants based on how much they smoked, identifying 240 light smokers (<10 cigarettes per day), 141 moderate smokers (10-19 cigarettes per day), and 136 heavy smokers ( ³20 cigarettes per day).

“Rates of crude corticosteroid use and the risk of corticosteroid‐flares were similar between all groups,” the authors wrote. “We found that heavy smokers were no more likely to develop corticosteroid dependence than those who had never smoked (HR .25, 95% CI .06‐1.03, P = .055) but it is possible that our sample (n = 136) could not detect a difference.”

According to the investigators, while the relationship between smoking status at diagnosis on the subsequent course of the disease is unclear, tobacco smoke exposure is linked to about half the risk of developing UC.

There have been conflicting results in past research where investigators compared the overall corticosteroid use between smokers and non-smokers.

In an earlier cohort study, data shows that reported smokers were less likely to undergo colectomy than non-smokers (32% vs. 42%, P =.04), while a 2016 meta-analysis indicated no major difference between the 2 groups in regard to colectomy or disease activity.

The study, “The impact of smoking and smoking cessation on disease outcomes in ulcerative colitis: a nationwide population‐based study,” was published online in Alimentary Pharmacology and Therapeutics.     
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