Hormone therapy initiation after the Women's Health Initiative.

Objectives: To describe hormone therapy (HT) initiation after the 2002 publication of the Women's Health Initiative.

Design: Observational cohort (1999-2003) of women ages 40 to 79 years, five health plans, used HT in July 2002 and subsequently discontinued or never used before August 2002.

Results: Of discontinuers, 15.8% (3,203 of 20,205) reinitiated HT. Reinitiation was higher among estrogen users (23.8%) versus estrogen with progestin users (11.3%), and lower among those with diabetes (relative risk [RR]=0.68, 95% CI: 0.61-0.76), cardiovascular disease (RR=0.87, 95% CI: 0.83-0.92), and hyperlipidemia (RR=0.83, 95% CI: 0.79-0.88). Only 2.3% (2,072 of 90,261) of never users initiated (August 2002 to December 2003). First-time initiation was associated with cardiovascular disease (RR=1.17, 95% CI: 1.10-1.25) and hyperlipidemia (RR=1.24, 95% CI: 1.17-1.33) and was less common among those with diabetes (RR=0.70, 95% CI: 0.63-0.79).

Conclusions: After the Women's Health Initiative, a minority of women reinitiated or became first-time initiators of HT. Women with cardiovascular disease, diabetes, and hyperlipidemia were less likely to reinitiate; women with cardiovascular disease and hyperlipidemia were more likely to be first-time initiators.