P430 Prognostic significance of serial faecal calprotectin in inflammatory bowel disease
Y. Zhulina1, Y. Cao2, K. Amcoff3, M. Carlson3, C. Tysk1, J. Halfvarson*1
1Örebro University, Department of Gastroenterology, Faculty of Medicine and Health, Örebro, Sweden, 2Örebro University, Clinical Epidemiology and Biostatistics, Faculty of Medicine and Health, Örebro, Sweden, 3Uppsala University, Department of Medical sciences, Gastroenterology Research Group, Uppsala, Sweden
Faecal calprotectin (FC) has consistently been shown to correlate with endoscopic activity in inflammatory bowel disease (IBD) patients. However, longitudinal monitoring of FC has rarely been employed beyond assessment of therapy response and post-hoc analyses of clinical trials. The reliance on single measurements of FC can be questioned considering dynamic nature of IBD. Our aim was to assess if consecutive measurements of FC every third month can be used to prospectively predict the risk of future flare in a cohort of IBD patients in clinical remission.
Patients 18 years and older, with a known diagnosis of IBD in clinical remission, were consecutively recruited at the outpatient clinic, Örebro University Hospital, Sweden. Patients provided faecal samples every third month until the first clinical relapse or end of the 2-year follow-up period. FC was analysed according to the manufacturer’s protocol (EK-CAL, Bühlmann Lab. AG, Switzerland).
In total, 104 IBD patients (Crohn’s disease n = 49 and ulcerative colitis n = 55) were included. Further, 50 patients were males and 54 females, and 37 patients relapsed and 67 remained in clinical remission. During the study, 519 faecal samples were obtained. The median FC concentration was already increased 3 months before the clinical relapse. A 101% increased risk of relapse was observed per unit of log2-transformed FC (HR 2.01; 95% CI 1.53–2.65; p < 0.001), which means that a doubled FC was associated with a 101% increased risk of flare. An interaction between FC and time was also observed (HR 0.80; 95% CI 0.75–0.86; p < 0.001), corresponding to a 20% decreased risk of relapse per 3 months period after the sample was obtained; in other words, the latest FC had the most pronounced effect. The associations between risk of relapse and concentration of FC, as well as duration since obtainment of faecal sample, remained significant when Crohn’s disease and ulcerative colitis patients were analysed separately.
Our data suggest that longitudinal monitoring of FC is informative to predict relapse in IBD. By consecutive measurement of FC every third month, we quantified the risk of relapse related to FC change and observed attenuation of the risk across time. Future studies should evaluate whether early medical intervention is useful for the prevention of subsequent relapse in asymptomatic patients with elevated FC level and to address the cost-effectiveness of this monitoring regimen.