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.