Reliability and validity of the Beliefs About Medication Scale in pediatric inflammatory bowel disease

Low adherence is a pervasive issue among youth with inflammatory bowel diseases (IBD), yet our understanding of perceived adherence barriers is hampered by a lack of validated instruments. This study sought to address this by evaluating the reliability and predictive validity of the Beliefs About Medication Scale (BAMS) among youth with IBD. Seventy-six youth (ages 11-18) with IBD who were prescribed a daily oral IBD medication completed baseline ratings of perceived adherence barriers via the BAMS. Parents provided information about patient demographic and disease factors. Subjective medication adherence was assessed via the medication adherence measure. Objective medication adherence was assessed via Medication Event Monitoring System (MEMS) Track Caps. BAMS subscales demonstrated adequate internal consistency ( αs = .78-.90) and test-retest reliability ( rs = .64-.79). BAMS subscales reliably distinguished between adherent and low adherent groups, though intent to adhere (IA) was the only independent predictor of adherence status. The BAMS holds promise as a tool for assessing adherence barriers among adolescents with IBD. IA may be of particular value in identifying adolescents at risk for low adherence.