# The 2017 Women’s Health Initiative study and use of hormone therapy: an emulated repeated cross-sectional study

## TL;DR

This study examined whether the 2017 update of the Women’s Health Initiative affected hormone therapy use in Taiwan, finding no significant impact.

## Contribution

The study introduces an emulated repeated cross-sectional design to analyze interval-censored data in population-based policy interventions.

## Key findings

- The 2017 WHI findings did not significantly affect HT use or menopause-related outpatient visits.
- Baseline characteristics before and after the 2017 study were not significantly different.
- The 2002 WHI trial had a confirmed negative impact on HT use, validating the study design.

## Abstract

Hormone therapy (HT) use among menopausal women declined after negative information from the 2002 Women’s Health Initiative (WHI) HT study. The 2017 post-intervention follow-up WHI study revealed that HT did not increase long-term mortality. However, studies on the effects of the updated WHI findings are lacking. Thus, we assessed the impact of the 2017 WHI findings on HT use in Taiwan.

We identified 1,869,050 women aged 50–60 years, between June and December 2017, from health insurance claims data to compare HT use in the 3 months preceding and following September 2017. To address the limitations associated with interval-censored data, we employed an emulated repeated cross-sectional design. Using logistic regression analysis, we evaluated the impact of the 2017 WHI study on menopausal symptom-related outpatient visits and HT use. In a scenario analysis, we examined the impact of the 2002 trial on HT use to validate our study design.

Study participants’ baseline characteristics before and after the 2017 WHI study were not significantly different. Logistic regressions demonstrated that the 2017 study had no significant effect on outpatient visits for menopause-related symptoms or HT use among women with outpatient visits. The scenario analysis confirmed the negative impact of the 2002 WHI trial on HT use.

The 2017 WHI study did not demonstrate any impact on either menopause-related outpatient visits or HT use among middle-aged women in Taiwan. Our emulated cross-sectional study design may be employed in similar population-based policy intervention studies using interval-censored data.

The online version contains supplementary material available at 10.1186/s12889-024-19089-2.