Gastroenterology

Gastroenterology

Volume 114, Issue 6, June 1998, Pages 1143-1150
Gastroenterology

Alimentary Tract
Oral contraceptive use and smoking are risk factors for relapse in Crohn's disease,☆☆

https://doi.org/10.1016/S0016-5085(98)70419-6Get rights and content

Abstract

Background & Aims: Lifestyle factors have been shown to influence prognosis in Crohn's disease. The purpose of this study was to prospectively assess the effects of smoking and oral contraceptive use on clinical relapse rates. Methods: Placebo-treated patients formed a prospective cohort, followed up for 48 weeks or until relapse. The influence of smoking and the use of oral contraceptives on relapse risk was examined by life-table analysis (log rank tests) and Cox proportional hazards modeling, taking into account demographic and disease characteristics. Results: Of 152 patients, 61 (40%) had a relapse. Univariate analysis showed unfavorable outcomes for women (P = 0.05), current smokers (P = 0.005), and use of oral contraceptives (P = 0.001). Recent surgery was associated with a decreased risk of relapse (P = 0.02). The Cox model retained current smoking vs. never smoking (hazard ratio, 2.1; 95% confidence interval, 1.1–4.2), oral contraceptive use (hazard ratio, 3.0; 95% confidence interval, 1.5–5.9), and medical compared with surgical induction of remission (hazard ratio, 2.1; 95% confidence interval, 1.0–4.2) as predictors of relapse. Ex-smokers did not have an increased risk. Finally, sex, age, time in remission, disease location, and disease duration were not significant predictors. Conclusions: Oral contraceptive use and smoking are associated with an increased risk of relapse in patients with Crohn's disease.

GASTROENTEROLOGY 1998;114:1143-1150

Section snippets

Patients

The analysis was based on placebo-treated patients participating in a multicenter, randomized, controlled clinical trial.25 Each of the 31 Canadian centers participating in the trial was responsible for obtaining ethical approval of the respective local Institutional Review Board. Patients were recruited after informed consent between January 1990 and January 1993. Inclusion criteria were age of at least 18 years and Crohn's disease confirmed by barium radiograph, endoscopy, macroscopic

Results

All 152 patients randomized to placebo treatment were included in the analysis. Demographic and disease characteristics are shown in Table 1. Eighty-eight of the patients were women (58%). The median age was 34.4 years (range, 18–82 years). About half of the patients had disease confined to the ileum. The current remission had been induced by surgery in 40 patients (26%). Thirty-nine percent of the patients were current smokers, 26% were ex-smokers, and 35% had never smoked. Ex-smokers were

Discussion

A large placebo-controlled clinical trial offered several advantages for efficiently examining risk factors for relapse in Crohn's disease. Placebo-treated patients may be considered as close as possible, under controlled circumstances, to be patients experiencing the natural course of the disease. Treatment effects that might otherwise mask the effects of risk factors are abolished. The prospective design, with exposure assessment during remission, and the focus on treatment assignment rather

Acknowledgements

The authors thank Dr. R. Brant (Department of Community Health Sciences, University of Calgary) for statistical advice; and Drs. R. J. Hilsden and C. MacArthur for thoughtful comments on the manuscript.

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    Address requests for reprints: Lloyd R. Sutherland, M.D., Department of Community Health Sciences, 3330 Hospital Drive Northwest, Calgary, Alberta, T2N 4N1, Canada. e-mail: [email protected]; fax: (403) 270-7307.

    ☆☆

    Dr. Timmer is a fellow of the German Academic Exchange Service.

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