Postmenopausal hormone therapy: less favourable risk-benefit ratios in healthy Dutch women

Objectives. To estimate the health effects of postmenopausal hormone therap y used for 10 or 20 years in a population of intermediate cardiovascular ri sk. Design. Using existing estimates of the effect of hormone therapy on rates of myocardial infarction, hip fracture and breast cancer, a proportional mu ltistage life table was generated to calculate the effects of use for 10 an d 20 years in a synthetic cohort of Dutch women aged 55 with an average and a high-risk profile for cardiovascular disease. Results. A woman of the general population who starts hormone therapy at ag e 55 for 10 years can prolong her life by 1 month and may postpone the occu rrence of first incidence of one of the diseases under consideration by 2.4 months. One excess breast cancer case is likely to occur per 5-6 averted c ases of first myocardial infarction or hip fracture. If she prolongs her us e to 20 years, the gain of life expectancy and disease-free life expectancy is doubled. The risk-benefit ratio worsens to one extra breast cancer per 3-4 averted cases of the preventable diseases. For a woman with a high-risk profile, the gains in health are about twice as high as for her counterpar t in the general population, and her risk-benefit ratio is also more favour able. Yet, the risk-benefit ratio still worsens for 20 as compared with 10 years of use. Conclusions. Women from the general population in the Netherlands and simil ar populations can achieve only a modest gain in life expectancy by using h ormones during 10 or 20 years following menopause. This is a consequence of the low incidence of myocardial infarction and hip fracture and the relati vely high incidence of breast cancer before the age of 75. Women at increas ed cardiovascular risk can benefit more from hormone therapy. But even amon gst these women, the risk of breast cancer incurred with long-term use offs ets much of the benefit that could accrue from changing the risk of heart d isease and hip fracture.