Economic impact of tibolone compared with continuous-combined hormone replacement therapy. In the management of postmenopausal women with climacteric symptoms in the UK.

OBJECTIVE: To estimate the economic impact of using tibolone 2.5 mg compared with 17 beta-estradiol 2 mg/norethisterone acetate 1 mg (E2/NETA) in postmenopausal women with climacteric symptoms.

DESIGN AND SETTING: This was a modelling study performed from the perspective of the UK's National Health Service (NHS).

METHODS: The clinical outcomes from a previously reported trial were used as the clinical basis for the analysis, which showed that 48 weeks' treatment with tibolone and E2/NETA significantly alleviated the climacteric symptoms experienced by postmenopausal women. These data were combined with resource utilisation estimates derived from a panel of 10 GPs and 3 gynaecologists, enabling us to construct a Markov model depicting changes in the health status of postmenopausal women. The model was used to estimate the expected NHS costs and consequences after 48 weeks' treatment with tibolone and E2/NETA.

MAIN OUTCOME MEASURES AND RESULTS: The mean expected direct healthcare cost of using tibolone and E2/NETA to manage postmenopausal women for 48 weeks was estimated to be 260 Pounds and 239 Pounds (1997/1998 prices) per patient, respectively. Starting hormone replacement therapy (HRT) with tibolone instead of E2/NETA was equally effective in alleviating climacteric symptoms (65.9 and 62.2%, respectively; p = 0.516) over 48 weeks and significantly reduced the incidence of vaginal bleeding by 36% (p < 0.0001) and breast tenderness by 57% (p < 0.0001) for a mean additional cost of 21 Pounds (ranging between -3 Pounds and 42 Pounds) per patient. The acquisition cost of HRT was the primary cost driver for tibolone-treated patients, whereas the cost of managing adverse events was the primary cost driver for E2/NETA-treated patients.

CONCLUSIONS: The true cost of prescribing tibolone and E2/NETA is impacted on by a broad range of resources, not only drug acquisition costs. Although the acquisition cost of tibolone is higher than that of E2/NETA, the difference in the expected NHS cost of the first year of treatment between the 2 HRTs is negligible. This is because of the higher incidence of adverse events among E2/NETA-treated patients, which also results in a higher continuation rate among tibolone-treated patients. Factors such as patient preferences should also be taken into consideration so that treatment choices are not decided solely on the basis of acquisition costs.