A simple biological score for predicting low risk of short-term relapse in Crohnʼs disease

Background In Crohn's disease, studies have evaluated the ability of biological markers to predict relapse in the next 12 to 18 months, without differentiating early from late relapses. The aim of this study was to look for biological markers of short-term relapse. Materials and methods In a previous therapeutic trial, patients with a medically induced clinical remission had biological markers evaluated and updated every 6 weeks. A Cox model with time-dependent covariates was used for analysis. Results Among the 71 patients, 38 had a relapse. Multivariate analysis selected 2 markers predictive of relapse: C-reactive protein >20 mg/L and erythrocyte sedimentation rate >15 mm. A binary biological predictive score was derived: "negative" when both were lower than their limits, "positive" when otherwise. The relative risk of short-term relapse for patients with a positive score compared to those with a negative score was 8.0 (95% confidence interval 2.8-22.9). Sensitivity of the score was 89% and specificity was 43%. Assuming a 10% relapse rate every 6 weeks, negative and positive predictive values were 97% and 15%, respectively. Conclusions This simple biological score can predict short-term maintenance of remission in Crohn's disease and may help physicians in the follow-up of patients in clinical remission.