Continuation rate of hormone replacement therapy in Hong Kong public health sector

To assess the 1-year continuation rate of HRT prescribed in Hong Kong public health sector and to identify factors affecting this continuation rate.

All women who received at least one dispensed prescription of estrogens between January 1998 and December 2000 from 36 specialist outpatient clinics of the Hospital Authority were selected, and observed for at least 2 years and at most 3 years. The duration of use and variables including age, types of hormones, routes of delivery, dose of estrogen, and prescribing specialty were retrieved from the central prescription database of the Hospital Authority.

Of 12,711 incident users of HRT, more than half were aged 50-59. Most (78.5%) of the users took conjugated equine estrogens (CEE) 0.625 mg or related products. Only a small proportion (3.0%) of women used CEE 0.3 mg. Initial estrogen prescriptions were written by gynaecologists in 86.7%. The overall 1-year continuation rate was 68.3%. The highest and lowest continuation rates were observed in women aged 40-49 and the two extreme age groups (35-39 and 70-79), respectively. Better continuation rate was observed in women taking estrogen-only therapy such as CEE or estradiol (overall 76.3%) than in women using continuous combined therapy (58.6%), sequential combined therapy (64.8%), or transdermal estrogen (60.6%). In the age group 60-69, the use of CEE 0.3 mg was associated with better continuation rate than CEE 0.625 mg.

Better continuation rate at 1 year was associated with age younger than 60, oral route of HRT and hysterectomy.