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An investigation of medication adherence to 5‐aminosalicylic acid therapy in patients with ulcerative colitis, using self‐report and urinary drug excretion measurements
Author(s) -
MOSHKOVSKA T.,
STONE M. A.,
CLATWORTHY J.,
SMITH R. M.,
BANKART J.,
BAKER R.,
WANG J.,
HORNE R.,
MAYBERRY J. F.
Publication year - 2009
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1111/j.1365-2036.2009.04152.x
Subject(s) - medicine , ulcerative colitis , odds ratio , urine , confidence interval , logistic regression , urinary system , medication adherence , drug , physical therapy , psychiatry , disease
Summary Background Non‐adherence to 5‐aminosalicylic acid (5‐ASA) medication can limit the established benefits of this therapy in ulcerative colitis (UC). Aim To determine rates and predictors of non‐adherence to 5‐ASA therapy in UC patients. Methods Medication adherence was assessed using self‐report data and urinary drug excretion measurements. Participants completed a study‐specific questionnaire and two validated questionnaires: Beliefs about Medicine Questionnaire (BMQ)‐Specific and Satisfaction with Information about Medicines Scale. Results A total of 169 participants provided self‐report adherence data; 151 also provided urine samples. Adherence rates were 111/151 (68%) according to self‐report and 90/151 (60%) according to urine analysis, but the two measures were not correlated (χ 2 = 0.12, P = 0.725). Logistic regression identified a significant association between self‐reported non‐adherence and younger age [odds ratio (OR) for increased age 0.954, 95% confidence interval (CI) 0.932–0.976] and also doubts about personal need for medication (OR for BMQ – Specific Necessity scores 0.578, 95% CI 0.366–0.913). For non‐adherence based on urine analysis, only South Asian ethnicity was independently associated with non‐adherence (OR 2.940, 95% CI 1.303–6.638). Conclusions Our observations confirm the difficulty of accurately assessing medication adherence. Nonmodifiable (younger age, South Asian ethnicity) and potentially modifiable (medication beliefs) predictors of non‐adherence were identified.