Objective Versus Subjective Assessment of Oral Medication Adherence in Pediatric Inflammatory Bowel Disease

Background: The objective was to examine the prevalence and frequency of oral medication nonadherence using l a multimethod assessment approach consisting of objective, subjective. and biological data in adolescents with inflammatory bowel disease (IBD). Methods: Medication adherence was assessed via pill Counts, patient/parent interview, and 6-thioguanine nucleotide (6-TGN)/6-methylmercaptopurine nucleotide (6-MMPN) metabolite bioassay in 42 adolescents with IBD. Pediatric gastroenterologists provided disease severity assessments. Results: The objective nonadherence prevalence was 64% for 6-MP/azathioprine (AZA) and 88% for 5-aminosalicylate (5-ASA) medications. whereas subjective nonadherence prevalence was 10% for 6-MP/AZA and 2% for 5-ASA. The objective nonadherence frequency was 38% for 6-MP/AZA and 49% for 5-ASA medications. and subjective nonadherence frequency was 6% for 6-MP/AZA and 3% for 5-ASA. The bioassay data revealed that only 14% of patients had therapeutic 6-TGN levels. Conclusions: The results indicate that objectively measured medication nonadherence prevalence is consistent with that observed ill other pediatric chronic illness populations. and that objective non-adherence frequency is considerable. with 40%-50% of doses missed by patients. Subjective assessments appeared to overestimate adherence. Bioassay adherence data. while compromised by pharmacokinetic variation. might be useful as a cursory screener for nonadherence with follow-up objective assessment. Nonadherence in 1 medication might also indicate nonadherence in other medications. Clinical implications and future research directions are provided.