TY - JOUR
T1 - Systematic Review and External Validation of Prediction Models Based on Symptoms and Biomarkers for Identifying Endoscopic Activity in Crohn's Disease
AU - Brand, Eelco C.
AU - Elias, Sjoerd G.
AU - Minderhoud, Itta M.
AU - van der Veen, Julius J.
AU - Baert, Filip J.
AU - Laharie, David
AU - Bossuyt, Peter
AU - Bouhnik, Yoram
AU - Buisson, Anthony
AU - Lambrecht, Guy
AU - Louis, Edouard
AU - Pariente, Benjamin
AU - Pierik, Marieke J.
AU - van der Woude, C. Janneke
AU - D'Haens, Geert R. A. M.
AU - Dutch Initiative on Crohn and Colitis
AU - Vermeire, S. verine
AU - Oldenburg, Bas
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Background & Aims: Endoscopic healing, an important target of treatment for Crohn's disease (CD), requires ileocolonoscopy, which is costly and burdensome. We investigated whether published noninvasive models (based on symptoms and biomarkers) to evaluate CD activity have sufficient accuracy to replace ileocolonoscopy. Methods: We performed a systematic review of published noninvasive diagnostic models to evaluate CD activity that used endoscopic features of activity (endoscopic activity) or healing as the reference standard. We externally validated these models for the outcome endoscopic activity (CD endoscopic index of severity scores, ≥3) using data from the a randomized controlled trial investigating tailored treatment with infliximab for active luminal Crohn's disease (TAILORIX) study (346 ileocolonoscopies in 155 patients) and the Utrecht Activity Index (UAI) study (93 ileocolonoscopies in 82 patients). We calculated the area under the receiver operating characteristic curves (AUROCs) for the models using data from these studies, and compared the performance of these models against measurements of fecal calprotectin (FC) and C-reactive protein (CRP). Results: We screened 5303 articles and identified 27 models (from 21 studies) for our analysis. Seven models could be validated externally; in the TAILORIX data set, these models identified patients with endoscopic activity with AUROC values ranging from 0.61 (95% CI, 0.51–0.70) to 0.81 (95% CI, 0.76–0.86). In this data set, the AUROC value for FC concentration was 0.79 (95% CI, 0.74–0.85) and the AUROC value for CRP level was 0.72 (95% CI, 0.66–0.77). The AUROC values for the validation in the UAI data set were similar. In the TAILORIX and/or UAI data set, 4 of the 7 models, as well as the FC and CRP assays, were able to identify patients with endoscopic activity with positive predictive values of 90% or more. Two of the 7 models (but not the FC or CRP values) identified patients without endoscopic activity with a negative predictive value (NPV) of 90% or more, leading to correct prediction of endoscopic healing in 3.2% to 11.3% of all patients. For example, applying the Herranz–Bachiller model (1 of 7 models) at a NPV of 92.1% and a positive predictive value of 91.9% correctly identified 35.7% of all patients in whom ileocolonoscopy could be avoided for expected endoscopic activity or healing but incorrectly identified 3.2% of all patients. Most ileocolonoscopies (66.5% in TAILORIX and 72.6% in the UAI of all ileocolonoscopies) could be avoided correctly based on concentrations of FC of 100 μg/g or less and 250 μg/g or higher. However, using this range of FC concentrations to identify patients who do not require ileocolonoscopy caused 18.7% of all patients in the TAILORIX cohort and 19.8% of all patients in the UAI cohort to be predicted incorrectly to have endoscopic activity or healing. Conclusions: In a systematic review and external validation of noninvasive models to identify patients with endoscopic activity of CD, we found only 2 of 7 models evaluated to have NPVs of 90% or more, however, leading to correctly predicted EH in only a small proportion of patients. Ileocolonoscopy therefore remains the mainstay to evaluate CD mucosal disease activity and healing.
AB - Background & Aims: Endoscopic healing, an important target of treatment for Crohn's disease (CD), requires ileocolonoscopy, which is costly and burdensome. We investigated whether published noninvasive models (based on symptoms and biomarkers) to evaluate CD activity have sufficient accuracy to replace ileocolonoscopy. Methods: We performed a systematic review of published noninvasive diagnostic models to evaluate CD activity that used endoscopic features of activity (endoscopic activity) or healing as the reference standard. We externally validated these models for the outcome endoscopic activity (CD endoscopic index of severity scores, ≥3) using data from the a randomized controlled trial investigating tailored treatment with infliximab for active luminal Crohn's disease (TAILORIX) study (346 ileocolonoscopies in 155 patients) and the Utrecht Activity Index (UAI) study (93 ileocolonoscopies in 82 patients). We calculated the area under the receiver operating characteristic curves (AUROCs) for the models using data from these studies, and compared the performance of these models against measurements of fecal calprotectin (FC) and C-reactive protein (CRP). Results: We screened 5303 articles and identified 27 models (from 21 studies) for our analysis. Seven models could be validated externally; in the TAILORIX data set, these models identified patients with endoscopic activity with AUROC values ranging from 0.61 (95% CI, 0.51–0.70) to 0.81 (95% CI, 0.76–0.86). In this data set, the AUROC value for FC concentration was 0.79 (95% CI, 0.74–0.85) and the AUROC value for CRP level was 0.72 (95% CI, 0.66–0.77). The AUROC values for the validation in the UAI data set were similar. In the TAILORIX and/or UAI data set, 4 of the 7 models, as well as the FC and CRP assays, were able to identify patients with endoscopic activity with positive predictive values of 90% or more. Two of the 7 models (but not the FC or CRP values) identified patients without endoscopic activity with a negative predictive value (NPV) of 90% or more, leading to correct prediction of endoscopic healing in 3.2% to 11.3% of all patients. For example, applying the Herranz–Bachiller model (1 of 7 models) at a NPV of 92.1% and a positive predictive value of 91.9% correctly identified 35.7% of all patients in whom ileocolonoscopy could be avoided for expected endoscopic activity or healing but incorrectly identified 3.2% of all patients. Most ileocolonoscopies (66.5% in TAILORIX and 72.6% in the UAI of all ileocolonoscopies) could be avoided correctly based on concentrations of FC of 100 μg/g or less and 250 μg/g or higher. However, using this range of FC concentrations to identify patients who do not require ileocolonoscopy caused 18.7% of all patients in the TAILORIX cohort and 19.8% of all patients in the UAI cohort to be predicted incorrectly to have endoscopic activity or healing. Conclusions: In a systematic review and external validation of noninvasive models to identify patients with endoscopic activity of CD, we found only 2 of 7 models evaluated to have NPVs of 90% or more, however, leading to correctly predicted EH in only a small proportion of patients. Ileocolonoscopy therefore remains the mainstay to evaluate CD mucosal disease activity and healing.
KW - Colonoscopy
KW - IBD
KW - PPV
KW - Response to Therapy
UR - http://www.scopus.com/inward/record.url?scp=85086573815&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.cgh.2019.12.014
DO - https://doi.org/10.1016/j.cgh.2019.12.014
M3 - Review article
C2 - 31881273
SN - 1542-3565
VL - 18
SP - 1704
EP - 1718
JO - Clinical Gastroenterology and Hepatology
JF - Clinical Gastroenterology and Hepatology
IS - 8
ER -