Published: 30 September 2002
Revised:  21 February 2025

Publications

Hormone Replacement Therapy - Letter to Healthcare Professionals

 

Information on this subject was updated in 2003 but may no longer be current. Read the 2003 information.

This letter was posted to all doctors and pharmacies on Wednesday 2 October 2002.

30 September 2002

 

 

 

 

Dear Health Professional

In July 2002, the Women's Health Initiative Study¹ published results, summarised below, demonstrating that the risks of routine combined oestrogen and progestogen hormone replacement therapy (HRT) outweighed the benefits.

Table 1. Summary of incidence of adverse events based on results from the WHI study. Data derived from women aged 50 to 79 years, after an average follow-up of 5.2 years.

Adverse Event	Relative Risk HRT vs placebo at 5.2 years (95% CI)	Change in number of adverse events per 10,000 women in one year
Breast cancer	1.26 (1.00-1.59)	8 extra
Heart disease	1.29 (1.02-1.63)	7 extra
Stroke	1.41 (1.07-1.85)	8 extra
Pulmonary embolism	2.13 (1.39-3.25)	8 extra
Colorectal cancer	0.63 (0.43-0.92)	6 fewer
Hip fracture	0.66 (0.45-0.98)	5 fewer

Following publication of the WHI study, the New Zealand Guidelines Group and the Medicines Adverse Reactions Committee (MARC) conducted independent reviews of the literature on the risks and benefits of combined HRT. The Guidelines Group key messages are enclosed and are supported by the MARC.

On completion of its review the MARC concluded that:

• Combined HRT should normally be used only where menopausal symptoms are disruptive to the quality of life of the woman;
• HRT should not be used for the primary or secondary prevention of coronary heart disease or stroke;
• In most circumstances, the risks of long term treatment outweigh the benefits; and combined HRT should not be used for longer than 3-4 years;
• Oestrogen-only HRT increases the risk of breast cancer and venous thromboembolism to a similar extent as combined HRT;
• All prospective and current users of HRT should be advised of the risks and benefits of oestrogen and progestogens;
• The need for continued treatment with HRT should be reviewed at the woman's next visit to her General Practitioner and thereafter on a yearly basis.

The MARC advice to limit the duration of HRT use raises questions about the role of HRT in the management of osteoporosis. The Committee will convene an expert advisory panel to advise Medsafe on this issue. The outcome will be made available to PHARMAC for their review of HRT medicines. Further advice and information will be published in Prescriber Update.

Yours sincerely

Stewart S Jessamine
Principal Technical Specialist

1. Writing Group for the Women's Health Initiative (WHI) Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: Principal results from the WHI randomized controlled trial. JAMA 2002;288:321-333.

Level 18, Grand Plimmer Tower, 2-6 Gilmer Terrace, P O Box 5013, Wellington.  Phone (04) 496 2000 Fax (04) 496 2229