How many biomarker measurements are needed to predict prognosis in Crohn's disease patients under infliximab?—A prospective study

Timely stratification of Crohn's disease (CD) is essential for patients' management. The use of noninvasive accurate biomarkers is key to monitor treatment and to pursue mucosal healing, the ultimate treatment endpoint in CD. We aimed to evaluate the performance of readily available biomarkers and develop risk matrices to predict CD progression. Data from 289 CD patients receiving infliximab (IFX) maintenance therapy for 2 years was collected; those patients were included in DIRECT, a prospective multicenter observational study. Disease progression was evaluated using two composite outcomes incorporating clinical and drug‐related factors, the first including IFX dose and/or frequency adjustments. Univariate and multivariable logistic regressions were used to calculate the odds ratios (OR) and to develop risk matrices. The isolated presence of anemia at least once during follow‐up was a significant predictor of disease progression (OR 2.436 and 3.396 [p≤ 0.001] for composite outcomes 1 and 2, respectively) regardless of confounding factors. Isolated highly elevated C‐reactive protein (CRP; >10.0 mg/L) and fecal calprotectin (FC; >500.0 μg/g) in at least one visit were also significant predictors, while milder elevations (3.1–10.0 mg/L and 250.1–500.0 μg/g) were only relevant when detected in at least two visits (consecutive or not). The combination of biomarkers in risk matrices had good ability to predict progression; patients simultaneously presenting anemia, highly elevated CRP and FC at least once had 42%–63% probability of achieving the composite outcomes. The combined evaluation of hemoglobin, CRP, and FC in at least one time point and their incorporation into risk matrices seems to be the optimal strategy for CD management, as data from additional visits did not meaningfully influence the predictions and may delay decision‐making.