Trajectories of oral budesonide use in Crohn's disease cohort of Tuscan patients (Italy)

Background: Crohn's disease (CD) is a chronic immune-mediated inflammatory disease of the gastrointestinal tract. Oral budesonide (OB) is indicated exclusively as first-line therapeutic approach for Crohn Disease. The drug should be used to achieve remission (9 mg/day for 4-8 weeks) and possibly maintenance (6 g/day) in a 12-months period. Objectives: To identify and characterize adherence trajectories of OB in CD patients and related patterns. Methods: In this retrospective cohort study, data were retrieved from administrative healthcare databases in Tuscany (Italy). Patients were included if they had a first record of a diagnosis of ICD-9 or disease exemption or a first record of dispensation of OB as CD patient, in the period from 6/1/2011 to 6/30/2016 (index date, ID). Patients < 18 years old at ID or with history of data before ID < 5 years or follow-up of data after ID < 3 years were excluded. Patients with autoimmune hepatitis, cancer and no dispensation of OB were excluded from CD cohort. We considered as covariates sex, age, and number of concomitant drugs in the month preceding the ID. We estimated adherence to OB monthly through the Medication Possession Ratio and computed trajectory of adherence treatment with a procedure consists into 3 steps: 1) computation of 24 statistical measures; 2) factor analysis; 3) cluster analysis. We described the adherence in the clusters. Results: 3333 patients were included CD cohort, among them 1262 were excluded for no dispensation of OB. 2071 were patients included in the computation of trajectory of OB use. Trajectories' curves showed three different clusters of adherences to OB, which identified subgroups of OB users. Cluster 1 (n= 932) is represented by a curve of adherence that rapidly decreased to 20-30% of adherence within 5 months. Instead, cluster 2 (n=604) and 3 (n=546) described patterns of a short therapy timing, with discontinuation occurring within about 2 and 4 months, respectively. Statistically significance differences were found between covariates across the clusters. Conclusions: Trajectories' curves, computed for OB users, showed three difference clusters of adherences. Adherence to OB seems in line with guideline recommendation, particularly for patients discontinuing the drug after 2 or 4 months (trajectories 2 and 3). Further analysis will be needed to characterize the identified clusters, in order to evaluate possible inappropriate use of OB (cluster 1), potential switch to other therapies (cluster 2 and 3).