Measure
As part of the larger QI initiative, self-report measures of barriers to oral and injectable anticoagulant medication adherence were created. Items were adapted from those included in the psychometrically validated Parent and Adolescent Medication Barriers Scales14with author permission and used to create four versions of a barriers measure (oral anticoagulant – patient report; oral anticoagulant – caregiver report; injectable anticoagulant – patient report; injectable anticoagulant – caregiver report). Qualitative feedback from patients, caregivers, and the multidisciplinary medical team regarding item comprehension and face validity was gathered and used to inform measure refinements. The final measures are included in Supplemental Table I.
Approximately 6 weeks into the QI initiative, two items assessing adherence were added to the barriers measure. The first item, “How many anticoagulant doses did you/your child miss in the past 7 days?,” was used to calculate the percentage of prescribed doses taken defined as\(\left(\frac{n\ prescribed\ doses\ in\ past\ 7\ days-n\ doses\ missed\ in\ past\ 7\ days}{n\ prescribed\ doses\ in\ past\ 7\ days}*100\right)\). The second item, “Did you/your child miss any anticoagulant doses in the past month?”, was used to obtain a dichotomous (yes/no) indicator of missed doses in the past month.