P551 Lack of adherence to infliximab in inflammatory bowel disease patients contributes to loss of response in Crohn’s disease

Abstract

Background Lack of adherence in patients with inflammatory bowel disease (IBD) is a relevant problem in our clinical practice. Non-adherence to anti-TNF increases healthcare costs. The aim of this study was both to measure adherence and also to study the factors and consequences related to non-adherence in patients with IBD under maintenance treatment with infliximab (IFX). Methods A prospective, observational cohort study was designed and patients with IBD under treatment with IFX were consecutively included. Adherence was measured with pharmacy refills and Morisky Medication Adherence Scale-8 (MMAS-8). Patients were systematically asked about adherence and the mean displacement days, the accumulated delay, the mean delay and the medication possession ratio (MPR) were calculated. MPR was calculated by dividing the number of days supplied within the refill interval by the number of days in the actual refill interval over 24 months. Potencial risk factors for non-adherence were evaluated: age, gender, disease duration, site of disease, behaviour of Crohn’s disease (CD), smoking status, educational level, marital status, type of housing, extraintestinal manifestations, previous surgery, concomitant treatments, anxiety and depression. Relapse was defined as a Harvey Bradshaw score > 4 in CD and a partial Mayo > 2 in ulcerative colitis (UC). The Mann-Whitney Wilcoxon U Test was used to distinguish the intergroup differences. Correlations were evaluated with Spearman rank correlation coefficients. Results Ninety patients with mean age 46 years (range: 22–85) were included. 49 (54.4%) were women and 63 (70%) had CD. Anxiety occurred in 38.9% of patients and depression in 78.9%. Three quarters of the patients were in clinical remission at inclusion. After 24 months of follow-up, 82 (91.1%) had delayed some dose of treatment, 35 (38.9%) had delayed on at least 7 days some dose of treatment, and 11 (12.2%) had not received some of the scheduled doses. The MPR was 87% (range 46–100). Lack of adherence was related to loss of response to IFX in CD (p = 0.035), but not in UC (p=0.078). In UC, lack of adherence was related with anxiety (p=0.046). The Spearman’s correlation between older age and non-adherence was 0.53 (p=0.006) in UC and 0.1 (p=0.308) in CD. Conclusion Lack of adherence is related to loss of response to IFX in CD. Non-adherence to IFX is high and strongly associated with age in UC. Older patients with UC are more prone to lack of adherence.