Hormone therapy and increased risk of psoriasis in reproductive-age and postmenopausal women: a nationwide cohort study and target trial emulation.

BACKGROUND

Hormone therapy (HT) is widely administered for contraception and menopausal symptom management. However, its impact on psoriasis risk remains unclear, requiring an evaluation across diverse age groups to inform clinical practice and optimize treatment strategies.

OBJECTIVES

To investigate the association between HT and the risk of psoriasis in reproductive-age and postmenopausal women.

METHODS

This study utilized both nationwide cohort design and target trial emulation, analysing data from Taiwan's National Health Insurance Database (2001-2021). Women over 20 years old without a prior history of psoriasis, ovarian cancer or breast cancer were included, and categorized into reproductive-age (≤ 50 years) and postmenopausal (> 50 years) groups. Women who initiated HT were assigned as the exposed group, while women without HT formed the comparison group. The primary outcome was the incidence of psoriasis over a 5-year period. The study applied inverse probability of treatment weighting (IPTW) and Cox proportional hazards models to estimate hazard ratios (HRs). Both intention-to-treat (ITT) and per-protocol (PP) analyses were performed to enhance the robustness of the findings.

RESULTS

In the postmenopausal cohort, comprising 1 482 302 HT users and 1 313 799 nonusers, the IPTW-adjusted HR for psoriasis in the ITT analysis was 1.48 [95% confidence interval (CI) 1.44-1.52]. The PP analysis indicated a more pronounced risk, with an HR of 5.93 (95% CI 5.66-6.22). Among the reproductive-age cohort, which included 3 849 721 HT users and 1 585 461 nonusers, the IPTW-adjusted HR in the ITT analysis was 1.93 (95% CI 1.90-1.99). In the PP analysis, the risk increased, showing an HR of 7.85 (95% CI 7.56-8.15). These findings highlight the significantly elevated psoriasis risk associated with HT, especially in younger women.

CONCLUSIONS

This study establishes an association between HT and an increased risk of psoriasis in both reproductive-age and postmenopausal women using a nationwide cohort design and target trial emulation. These findings further highlight the potential influence of hormonal factors on psoriasis development. Clinicians should remain attentive to early signs of psoriasis in women receiving HT to ensure timely recognition and management.