Studies of compliance with delayed-release mesalazine therapy in patients with inflammatory bowel disease

BACKGROUND: Non-compliance with maintenance mesalazine therapy may be a risk factor for relapse in inflammatory bowel disease, but the prevalence and determinants of non-compliance are unknown. AIM: To study the prevalence and determinants of non-compliance in patients with inflammatory bowel disease. METHODS: Out-patients receiving delayed-release mesalazine were studied. Compliance was determined by direct enquiry and by analysis of urine samples for 5-aminosalicylic acid/N-acetyl-5-aminosalicylic acid. Potential determinants of compliance were assessed. RESULTS: Ninety-eight patients were studied. Forty-two patients (43%) reported taking <80% of their prescribed dose. Logistic regression revealed the independent predictors of non-compliance to be three-times daily dosing [odds ratio (OR), 3.1; 95% confidence interval (CI), 1.8-8.4] and full-time employment (OR, 2.7; 95% CI, 1.1-6.9). Urine from 12 patients (12%) contained no detectable 5-aminosalicylic acid/N-acetyl-5-aminosalicylic acid, and 18 patients (18%) had levels below those expected. Depression was the only independent predictor of complete non-compliance (OR, 10.5; 95% CI, 1.8-79.0), and three-times daily dosing was the only independent predictor of partial non-compliance (OR, 3.7; 95% CI, 1.8-8.9). Self-reporting correctly identified 66% of patients judged to be non-compliant on urinary drug measurement. CONCLUSIONS: Non-compliance with maintenance mesalazine therapy is common in patients with inflammatory bowel disease. Three-times daily dosing and full-time employment are predictors of partial non-compliance, whilst depression is associated with complete non-compliance. Self-reporting detects most non-compliant patients.