Objective versus subjective assessment of oral medication adherence in pediatric inflammatory bowel disease

Authors

  • Kevin A. Hommel PhD,

    Corresponding author
    1. Center for the Promotion of Treatment Adherence and Self-Management, Cincinnati, Ohio
    2. Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
    3. University of Cincinnati College of Medicine, Cincinnati, Ohio
    • Cincinnati Children's Hospital Medical Center, Center for the Promotion of Treatment Adherence and Self-Management, Division of Behavioral Medicine and Clinical Psychology, 3333 Burnet Ave. – MLC 7039, Cincinnati, OH 45229-3039
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  • Christine M. Davis MS,

    1. The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
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  • Robert N. Baldassano MD

    1. The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
    2. University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
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Abstract

Background: The objective was to examine the prevalence and frequency of oral medication nonadherence using 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 in other pediatric chronic illness populations, and that objective nonadherence 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.

(Inflamm Bowel Dis 2008)

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