Love BL, Johnson J, Hardin JW and Schulz R
Background: Oral 5-aminosalicylic acid (5-ASA) therapy is the first choice therapy for ulcerative colitis (UC), and adherence to therapy is important for long-term clinical improvement. Objective: To assess the relationship between dosing frequency, pill burden, clinical outcomes and medication adherence in patients receiving various 5-ASA formulations.
Methods: A single center, cross-sectional study was conducted in outpatients diagnosed with ulcerative colitis and prescribed aminosalicylates during a 3.5 year period. Medication adherence was quantified using the medication possession ratio (MPR), and non-adherence was defined as taking less than 80% of the prescribed dose. Demographic data, 5-ASA medication fill history and treatment outcomes data were collected. Clinical outcomes were assessed including surgery, hospitalization, emergency department (ED) visit, and documented flares. Logistic regression was used to model the odds of adherence to 5- ASA based on medication and dosing frequency.
Results: Non-adherence was observed in 66 (52.4%) of the 126 enrolled subjects. The median adherence rate in all patients was 78.2% (IQR 39.3). Most patients received either balsalazide (38.9%) or mesalamine delayed release (DR) tablets [Asacol®] (31.8%). Very few subjects received 5-ASA once or twice daily (25.4%). Significant differences were observed between dosing frequency and daily pill burden when comparing “adherent” and “nonadherent” patients. Patients receiving mesalamine MMX [Lialda®], mesalamine DR, and sulfasalazine were more likely to be adherent compared to balsalazide. No significant association was noted between clinical outcomes and medication adherence.