N. F. Col, M. H. Eckman, R. H. Karas, S. G. Pauker, R. J. Goldberg, E. M. Ross, R. K. Orr and J. B. Wong
Division of Clinical Decision Making, Informatics, and Telemedicine, Department of Medicine, New England Medical Center and Tufts University School of Medicine, Boston, Mass 02111, USA. nananda.col@es.nemc.org

OBJECTIVE: To examine the effect of hormone replacement therapy on life expectancy in postmenopausal women with different risk profiles for heart disease, breast cancer, and hip fracture.

DESIGN: Decision analysis using a Markov model. Published regression models were used to link risk factors to disease incidence and to estimate the lifetime risks of developing coronary heart disease (CHD), breast cancer, hip fracture, and endometrial cancer. The impact of hormone therapy on disease incidence was estimated from published epidemiologic studies.

SETTING: Mathematical model applicable to primary care.

INTERVENTIONS: Treatment with hormone replacement therapy or no hormone replacement therapy.

MAIN OUTCOME MEASURE: Life expectancy.

RESULTS: Hormone replacement therapy should increase life expectancy for nearly all postmenopausal women, with some gains exceeding 3 years, depending mainly on an individual's risk factors for CHD and breast cancer. For women with at least 1 risk factor for CHD, hormone therapy should extend life expectancy, even for women having first-degree relatives with breast cancer. Women without any risk factors for CHD or hip fracture, but who have 2 first-degree relatives with breast cancer, however, should not receive hormone therapy.

CONCLUSIONS: The benefit of hormone replacement therapy in reducing the likelihood of developing CHD appears to outweigh the risk of breast cancer for nearly all women in whom this treatment might be considered. Our analysis supports the broader use of hormone replacement therapy.