Objective: To estimate the rate of therapy continuation among women using six different hormone replacement therapies (HRTs).
Design: A retrospective, longitudinal analysis of pharmacy claims data was conducted for 7,120 women who were new users of six HRT regimens. Continuation rates of therapies were examined at the end of the 9-month period. In addition, the odds ratio of continuation for each product was determined using a logistic model, which controlled for the potential influence of a patient's age and a provider's age, gender, specialty, and geographical location.
Results: Treatment continuation rates at the end of the 9-month period were significantly higher among patients prescribed oral 1 mg norethindrone acetate/5 μg ethinyl estradiol (EE) (femhrt, Pfizer Inc, New York, NY, USA) compared with other HRT regimens. Patients prescribed 1 mg norethindrone acetate/5 μg EE were 52% more likely to continue therapy compared with patients prescribed 0.625 mg conjugated equine estrogens/2.5 mg or 5 mg medroxyprogesterone acetate (Prempro, Wyeth, Madison, NJ, USA). Significantly higher rates of therapy continuation were seen in women aged 55 years or older, those who did not switch HRT during the analysis, those who received care in the central and northeast regions of the United States, and those who were seen by obstetricians/gynecologists (v primary care physicians) or female (v male) providers.
Conclusions: The higher rates of treatment continuation seen with newer continuous combined HRTs, such as 1 mg norethindrone acetate/5 μg EE, may lead to improved long-term compliance and, therefore, better protection against osteoporosis in postmenopausal women.