National use of postmenopausal hormone therapy: annual trends and response to recent evidence.

CONTEXT: Postmenopausal hormone therapy use increased dramatically during the past 2 decades because of a prevailing belief in its health benefits. Recent evidence from randomized trials published in July 2002 demonstrated adverse cardiovascular disease events and other risks with hormone therapy in the form of oral estrogen combined with progestin.

OBJECTIVE: To describe patterns of hormone therapy use from 1995 until July 2003, including the impact of recent evidence.

DESIGN, SETTING, AND POPULATION: Two databases were used to describe national trends in hormone therapy use from January 1995 to July 2003. The National Prescription Audit database provided data on the number of hormone therapy prescriptions filled by retail pharmacies and the National Disease and Therapeutic Index database provided data on patient visits to office-based physicians during which hormone therapy was prescribed.

MAIN OUTCOME MEASURES: Annual number of hormone therapy prescriptions and characteristics of visits to physicians during which hormone therapy was prescribed.

RESULTS: Annual hormone therapy prescriptions increased from 58 million in 1995 to 90 million in 1999, representing approximately 15 million women per year, then remained stable through June 2002. Adoption of new oral estrogen/progestin combinations, primarily Prempro, accounted for most of this growth. Obstetrician/gynecologists provided more than 70% of hormone therapy prescriptions, and more than one third of patients were older than 60 years. Following the publication of trial results in July 2002, hormone therapy prescriptions declined in successive months. Relative to January-June 2002, prescriptions from January-June 2003 declined by 66% for Prempro and 33% for Premarin. Small increases were observed in vaginal formulations and in new prescriptions for low-dose Premarin. If prescription rates observed through July 2003 remain stable, a decline to 57 million prescriptions for 2003, similar to the rate in 1995, is projected.

CONCLUSIONS: Clinical practice responded rapidly to recent evidence of harms associated with hormone therapy. Since July 2002, many patients have discontinued hormone therapy or are tapering to lower doses.