Adherence to postmenopausal hormone therapy during the year after the initial prescription: A population-based study.

OBJECTIVE: In randomized trials a higher proportion of women prescribed continuous combined hormone replacement therapy complete the full course of treatment compared with those prescribed sequential therapy. We sought to determine adherence to hormone therapy in a less-selected population. STUDY
DESIGN: Women enrolled in a prepaid health plan participated in a telephone interview 12 to 15 months after newly initiating use of hormone replacement therapy. The interview elicited information on whether the women were still taking the hormones as first prescribed and reasons for switching or discontinuation. A computerized pharmacy database was used to determine initial doses, prescription renewal, and dates of switching or discontinuation.
RESULTS: The proportion continuing the originally prescribed hormone regimen at 1 year was higher among continuous combined therapy users (68.9%, 62/90) than among sequential therapy users (54.4%, 62/114). Women who initiated continuous combined therapy were less likely to have switched regimens (10.0%) than were sequential users (20.2%; relative risk, 0.5; 95% confidence interval, 0.2-1.0) but only somewhat less likely to have discontinued use (21.2% vs 25.4%; relative risk, 0.7; 95% confidence interval, 0.4-1.3). Examined as a whole, women prescribed continuous combined therapy were less likely than those prescribed sequential therapy to quit or switch during the first year (relative risk, 0.6; 95% confidence interval, 0.4-1.0).
CONCLUSION: Although adherence was higher among women prescribed continuous combined hormone replacement therapy than sequential therapy, the high level of nonadherence in both groups suggests room for improvement of menopausal therapies so that women find them acceptable for sustained use.