The extent and determinants of prescribing and adherence with acid-reducing medications: a national claims database study.

OBJECTIVES: No community-based, large-scale studies have examined the extent of prescribing acid-reducing medications or adherence and persistence to these medication regimens.
METHODS: We conducted a retrospective cohort study of patients with Barrett's esophagus (BE) and gastroesophageal reflux disease (GERD) without BE, diagnosed between 2000 and 2005, who had undergone an upper endoscopy within 1 year through a managed care plan in the United States. We identified filled prescriptions for oral proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) within 365 days after the index date of BE or GERD, and several measures of adherence (medication-ownership ratio (MOR)) and persistence (length of therapy, fill-refill ratio, discontinuation rate) for PPI treatment.
RESULTS: We identified 10,159 patients with BE and 48,965 GERD patients with no BE. The mean duration of filled PPI prescriptions accounted for only 30.2% of the available year after the index date, whereas that of either PPI or H2RA prescriptions accounted for only 31.7%. PPI prescriptions were filled by 66.6 and 60.4% of patients with and without BE, respectively. These proportions declined significantly between 2000 and 2005. For those with at least one prescription, the median duration of therapy was 241 days for PPIs and 159 for H2RAs. Both groups had low MOR and length of treatment and high discontinuation rates; however, adherence and persistence were significantly higher in BE than in non-BE patients, and significantly lower in 2005 than in 2000.
CONCLUSIONS: The use of prescription PPIs or H2RAs, as well as adherence and persistence with these medications, is lower than expected. The absence of BE and more recent diagnosis are associated with even lower prescription rates.