Main findings
This large population based matched cohort study estimated the long-term effects of HRT on the hazards of all-cause mortality of 105,199 healthy women aged 46 to 65 years at first prescription compared to 224,643 matched healthy controls, using primary care data from 1984 to 2017. Our study found that during this long follow-up, oestrogen-only HRT was not associated with significantly increased or decreased hazards of all-cause mortality in any age group, and combined HRT was associated with a significantly decreased risk of death from all causes.