Background: Because natural progesterone is poorly absorbed and rapidly metabolized, synthetic derivatives of progesterone, such as medroxyprogesterone acetate (MPA), are used in combination with estrogen in hormone replacement therapy. A micronized form of natural progesterone is available that is readily absorbed and reaches peak serum concentrations from 1 to 4 hours after administration.
Objective: The purpose of this study was to compare the quality of life (QOL), menopausal symptoms, and costs associated with a natural micronized progesterone (MP) formulation versus MPA as add-on therapy to estrogen in hormone replacement for post-menopausal women.
Methods: This prospective, multicenter, randomized, fixed-dose, open-label, parallel-group study enrolled postmenopausal, otherwise healthy, nonhysterectomized women 45 to 65 years of age who had been amenorrheic for > or =6 months and exhibited symptoms of estrogen deficiency. All women received 0.625 mg conjugated equine estrogens on days 1 to 25 of a 30-day cycle; on days 12 to 25, women were randomized to receive either MP 200 mg or MPA 5 mg; patients were followed for 9 months. QOL, the primary end point, was measured at baseline and months 3, 6, and 9 using the 36-Item Short-Form Health Survey (SF-36), the Nottingham Health Profile (NHP), and the condition-specific Women's Health Questionnaire (WHQ). Bleeding pattern, compliance, menopausal symptoms, and cost were evaluated as secondary end points. Costs (in 1997 Canadian dollars) were assessed from the societal perspective and included costs of study medication, hormone therapy monitoring, concomitant medication, outpatient resources, out-of-pocket expenses, and patient and caregiver time loss.
Results: A total of 182 women were enrolled; 89 received MP and 93 received MPA. Improvements in climacteric symptoms were observed from baseline to month 9 for both treatments. Mean scores on all domains of the SF-36 at month 9 were greater than scores at baseline in both treatment groups but the increases were not statistically significant. All domains within the NHP and WHQ improved significantly over this period for both groups (P < or = 0.008). Only patients receiving MP showed specific improvements in the menstrual problems and cognitive domains of the WHQ. The difference in average 9-month cost per patient was not statistically significant, at Can 367 dollars +/- 120 dollars and Can 360 dollars +/- 369 dollars for patients receiving MP and MPA, respectively.
Conclusions: MP is a clinically effective, well-tolerated, and cost-comparable alternative to MPA.