Postmenopausal hormonal support: discontinuation of raloxifene versus estrogen

Objective: To determine possible differences in continuation among women in itiating treatment with the selective estrogen receptor modulator raloxifen e, versus those initiating treatment with estrogen-containing regimens. Design: A pharmacy prescription database search for refill patterns. The st udy subjects were members of Kaiser Foundation Health Plan, a large health maintenance organization; 1,394 women age greater than or equal to 60 years who filled index prescriptions for either raloxifene (n = 331) or systemic estrogens (n = 1,063) between April 1998 and March 1999. The main outcome measure was discontinuation based on prescription refill patterns through D ecember 2000. Results: At 24 months, the probabilities of discontinuing were 56% for wome n starting raloxifene compared to 72% for women starting estrogens. The lik elihood of discontinuation was significantly less among women starting ralo xifene than among those starting estrogen (hazard ratio = 0.75; 95% confide nce interval = 0.64-0.88). Adjustments for age and prescriber specialty did not affect the risk. Conclusions: We conclude that discontinuation of estrogen by women well bey ond the age of menopause is high; more than two-thirds discontinue within 2 years of starting. Women starting therapy with raloxifene are 25% percent less likely to discontinue their medication than those starting estrogen, p roviding some promise that long-term benefits of raloxifene may be more eas ily achieved than those of estrogen.