Hormone replacement therapy: prevalence, compliance and the 'healthy women' notion

The objective of this study was to assess the current trends of hormone replacement therapy (HRT) use, including rates of use, length of use, continuation rates and characteristics of users and non-users and to examine the hypothesis that 'healthy women' are more likely to be users of HRT.

Analysis was carried out of three representative South Australian population studies in 1991, 1993 and 1995 comprising 3019, 3004 and 3016 personal interviews, respectively.

Current use (and ever-use) of HRT in all women aged 50 years and over rose from 13.2% (26.7%) in 1991, to 21.2% (31.9%) in 1993 and 26.0% (40.5%) in 1995. Highest use is now in the 55-59-year age group where, in 1995, current use was 50.9% and ever use was 69.0%. Median compliance rates with HRT rose from 24 months in 1991 to 60 months in 1995 for current users aged 50 years of age or above. The pattern of increasing use of HRT is not consistent across age groups. Analyses of the 1995 data show that, in contrast with increasing rates of current use in women over 55 years, there was no overall change in rates for women below this age. There were no statistically significant differences in health indicators, e.g. blood pressure, smoking, cholesterol levels or body mass index between users and non-users of HRT. However, users reported significantly higher rates of previous osteoporosis and hysterectomy.

Prevalence rates of HRT use are increasing together with compliance rates and this may reflect increased confidence with HRT therapy. Users of HRT have an increased rate of mammography compared to non-users and this may contribute to earlier detection and, therefore, increased estimates of breast cancer in HRT users. There was no support from the 1995 data for a 'healthy women' hypothesis among HRT users.