Effect of clinical trial publicity on HRT prescribing in Ireland

To evaluate the effect of publicity surrounding the Women's Health Initiative (WHI) and Million Women (MW) studies on prescribing of all hormone replacement therapy (HRT) preparations and bisphosphonates in Ireland.

The General Medical Services (GMS) prescription database was used to identify the study population. Prescriptions were identified for HRT and bisphosphonate preparations [using WHO Anatomical Therapeutic Chemical (ATC) classification codes] in female patients aged 45-69 years in Ireland during a 4-year study period (January 2001-December 2004). Prescription rates were calculated monthly. Prevalence and incidence of HRT use was examined.

There was a significant reduction in prevalence for all HRT preparations following the WHI trial (test for change in trend p<0.0001), which persisted after the MW study. The incidence of combined oestrogen/progestogen HRT declined after the WHI trial (test for change in trend p=0.004). Bisphosphonate prescribing showed a significant increase throughout the study period (p<0.0001).

The findings suggest that coverage surrounding the publication of clinical trials appears to have had a negative impact on the rate of HRT prescribing. The findings regarding the coincident increase in use of bisphosphonates may suggest that prescribers and users were less likely to regard HRT as an appropriate therapy in the management of osteoporosis for some time before guidance was issued by the regulatory authorities.