Patient noncompliance with hormone replacement therapy: a nationwide estimate using a large prescription claims...

The purpose of this investigation was to use a large prescription claims database to characterize noncompliance with hormone replacement therapy (HRT).

A retrospective longitudinal analysis was conducted among 28,718 women aged 40-59 years who were new HRT users. In the present study, HRT was defined as an oral estrogen (with or without progestin in separate prescribing) or as an oral estrogen combination with 21 or more recommended therapy days for every 28 calendar days. Compliance was determined by constructing a ratio of the total days of HRT received during the follow-up period divided by the total number of days in the follow-up period (365 days). An individual with a medication availability ratio less than 0.75 was considered to be noncompliant.

After 1 year, 54.4% of the study subjects were noncompliant with HRT. Noncompliance was associated with younger age, living in the southern region of the United States, and not having an obstetrician/gynecologist as the initial prescriber.

Noncompliance with HRT in the general population is higher than that reported in randomized clinical trials, suggesting that women are not benefiting optimally from therapy and that they are at risk for unnecessary morbidity and mortality from osteoporosis and cardiovascular disease. Increased efforts to improve long-term HRT compliance are urgently needed.