Risk matrix model for prediction of colectomy in a population-based study of ulcerative colitis patients (the IBSEN study)

Abstract

Objectives: Identifying ulcerative colitis (UC) patients with increased risk of colectomy is essential for appropriate treatment. We aimed to develop a prediction model assessing the risk of having colectomy within the first 10 years after diagnosis. Material and methods. A population-based inception cohort of UC patients diagnosed in south-eastern Norway between 1990 and 1994 has been followed for 10 years. Altogether 519 patients were recruited including 49 patients who were colectomized. Based on the best-fitted multivariate model, the probabilities of colectomy were computed for selected levels of baseline covariates, and the results arranged in a prediction matrix. The following risk factors at diagnosis were analyzed: age, smoking, sex, disease extent, weight loss and fever and need for systemic steroids. Biochemical markers included C-reactive protein (CRP, <30 or ≥30 mg/l); erythrocyte sedimentation rate (ESR, <30 or ≥30 mm/h) and hemoglobin (Hgb, <10.5 or ≥ 10.5 g/dL). Results. Extent of disease, age (<40 years, ≥40 years), need for systemic steroids and CRP or ESR (<30 or ≥30) at diagnosis were independently associated with colectomy and were combined in a prediction matrix. The probabilities of colectomy during the follow-up period ranged from 2.6% to 40.1% depending on the combination of predictors at diagnosis. Conclusions. Our prediction model revealed significant differences in the probability of undergoing colectomy during a 10-years course of disease, which supports an early individualized treatment approach in UC.

Key Words:

• colectomy
• population-based
• prognosis
• risk factors
• ulcerative colitis

Acknowledgments

This study was financially supported by MSD Norway and Janssen Biological B.V. We thank the following members of the IBSEN Study Group of gastroenterologists for participating in this study: Morten Vatn and Idar Lygren, Oslo University Hospital, Oslo; Jørgen Jahnsen, Akershus University Hospital, Lillestrøm; Ole Høie, Sørlandet Hospital, Arendal; Magne Henriksen, Østfold Hospital, Fredikstad; Njål Stray, Diakonhjemmet Hospital, Oslo; Tomm Bernklev and Jostein Sauar, Telemark Hospital, Skien. Conception and design of the study: ICS, MC, BM. Generation, collection, assembly, analysis and/or interpretation of data: ICS, MLH, MC, BM. Drafting or revision of the manuscript: ICS, MLH, MC, BM. Approval of the final version of the manuscript: ICS, MLH, MC, BM.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.