Morbidity analysis at follow-up
Hypertension and peripheral vascular disease were the commonest conditions to be diagnosed after study entry for both cases and controls (Table S5). The prevalence of hypertension was around 10% higher in oestrogen-only users than in non-users. Osteoporosis was the next most common condition to be diagnosed in both groups. At follow-up, cases had relatively more oophorectomies and hysterectomies. The prevalence of most chronic medical conditions was slightly higher in cases than in the controls, but there were more missing records in controls than in the cases.
The Kaplan-Meier plots (Figure S3) show that combined HRT users developed less Type 2 diabetes at all time points over the entire follow-up period. Until 10 years of follow-up, there were no differences in heart failure prevalence among the groups. However, after 10 years, both oestrogen-only HRT users and non-users developed more heart failure. Both combined HRT and oestrogen-only HRT users developed more breast cancer than the non-users, but the proportion is slightly higher in the combined HRT group. There were lower probabilities of osteoporosis diagnosis among the combined HRT users after 10 years of follow-up. There was no difference in the probabilities of dementia diagnosis among all groups up-to 18 years of follow-up. After 18 years, oestrogen-only HRT users developed slightly more dementia.