Hormone Replacement Therapy May Increase Risk of Severe Asthma Exacerbation in Women

Sarfaroj Khan 


March 19, 2021


  • Previous but not current use of hormone replacement therapy (HRT) and its subtypes (oestrogen-only and combined oestrogen/progestogen) and long-term use were associated with an increased risk of severe asthma exacerbation in peri- and postmenopausal women with asthma.

Why this matters

  • Although current findings do not suggest changes in asthma management in peri-menopausal and postmenopausal women, studies uncovering the mechanisms through which HRT impact on clinical outcomes of asthma are needed.

Study design

  • Researchers used the population-based, Optimum Patient Care Research Database to construct a 17-year retrospective cohort of peri-menopausal and postmenopausal (age, 46-70 years; n=31,656) women with asthma. The 17-year follow-up resulted in 366,678 person-years of follow-up time.

  • Association of HRT use, its subtypes and duration of use with severe asthma exacerbation was evaluated.

  • Funding: Asthma UK and Health Data Research UK.

Key results

  • At baseline, 22% of women were using any HRT, 11% combined HRT and 11% oestrogen-only HRT.

  • Compared with non-HRT use, previous use of any HRT (adjusted incidence rate ratio [aIRR], 1.24; 95% CI, 1.22-1.26), combined oestrogen/progestogen HRT (aIRR, 1.28; 95% CI, 1.25-1.31) and oestrogen-only HRT (aIRR, 1.18; 95% CI, 1.14-1.21) was associated with an increased risk of severe asthma exacerbation.

  • Current use of any HRT was associated with a small increased risk of severe asthma exacerbation (aIRR, 1.07; 95% CI, 1.04-1.09) while combined oestrogen/progestogen and oestrogen-only HRT showed no significant association.

  • Compared with non-HRT use, any duration of HRT use was associated with an increased risk of severe asthma exacerbation:

    • 1-2 years (aIRR, 1.16; 95% CI, 1.13-1.19);

    • 3-4 years (aIRR, 1.43; 95% CI, 1.38-1.48); and

    • >5 years (aIRR, 1.32; 95% CI, 1.28-1.36).

  • The risk estimates were greater in lean women (body mass index [BMI], <25 kg/m2) than heavier women (BMI, 25-29.9 kg/m2 and ≥30 kg/m2) and higher in smokers than non-smokers.


  • Risk of confounding.


Nwaru BI, Shah SA, Tibble H, Pillinger R, McLean S, Ryan D, Critchley H, Hawrylowicz CM, Simpson CR, Soyiri IN, Appiagyei F, Price D, Sheikh A. Hormone replacement therapy and risk of severe asthma exacerbation in peri-menopausal and post-menopausal women: 17-year national cohort study. J Allergy Clin Immunol Pract. 2021 Mar 8 [Epub ahead of print]. doi: 10.1016/j.jaip.2021.02.052. PMID: 33705997.  View full text 

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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