because it captures both quantity and dosage interval; however,
claims database analyses and patient-reported adherence
remain the most common methodologies employed due to the
ability of conducting large studies quickly and at relatively low
cost.14,15
Persistence refers to the time during which a patient remains
on a prescribed medication after initiating therapy. While persistence
can be measured directly by patient questionnaires
and claims analyses, it may also be measured indirectly from
discontinuation rates reported in observational and randomized
controlled trials (RCTs).11 While RCTs employ a structured
program of care that may result in low discontinuation rates
compared with the real-world patient experience, trends of
discontinuation over time, as well as reasons for discontinuation
reported in RCTs, may yield important information on
persistence.
Many comprehensive literature reviews have been
conducted on the adherence and persistence to chronic