BACKGROUND AND PURPOSE:

• Nwaru et al. (BMJ Thorax, 2020) examined the link between use of hormonal contraceptives and risk of severe asthma exacerbation in reproductive-age women with asthma

METHODS:

• Retrospective cohort study
• Data sources
  • Optimum Patient Care Research Database (OPCRD): a population-based longitudinal, anonymized primary care database
  • 630 primary care practices with  >6 million patients
  • 17-year (January 2000 to December 2016) cohort
• Population
  • Women ages 16 to 45 years old
  • Asthma diagnosis
• Exposures
  • Hormone contraceptives
• Study design
  • Data on hormonal contraceptive use, subtype and duration were extracted
  • Severe asthma exacerbation was defined according to recommendations of the European Respiratory Society/American Thoracic Society
    • Asthma-related hospitalization
    • Emergency department visits due to asthma
    • Oral corticosteroid prescriptions
  • Mixed-effects regression analysis used for calculations
• Goal of study
  • To determine association of hormonal contraceptives with severe asthma exacerbation

RESULTS:

• 83,084 women with asthma | 456,803 person-years of follow-up time
• At baseline
  • Women using any hormonal contraceptives: 34%
  • Women using combined (estrogen/progestogen): 25%
  • Women using progestogen only: 9%
• The following were associated with reduced risk of severe asthma exacerbation vs non-use
  • Previous use of any hormonal contraceptive
    • Incidence rate ratio (IRR) 0.94 (95% CI, 0.92 to 0.97)
  • Current use of any hormonal contraceptive
    • IRR 0.96 (95% CI, 0.94 to 0.98)
  • Previous use of combined hormonal contraceptive
    • IRR 0.92 (95% CI, 0.87 to 0.97)
  • Current use of combined hormonal contraceptive
    • IRR 0.93 (95% CI, 0.91 to 0.96)
  • Longer duration of use of hormonal contraceptives
    • 3 to 4 years
      • IRR 0.94 (95% CI, 0.92 to 0.97)
    • 5+ years
      • IRR 0.91, 95% CI,  0.89 to 0.93

CONCLUSION:

• Hormonal contraceptive use was associated with reduced incidence of severe asthma events in reproductive-age women
• The authors had planned to study route of administration (e.g., oral vs intrauterine) but “information was poorly and inconsistently recorded”
• The authors state that

Further longitudinal studies are required to confirm these findings, as well as mechanistic studies investigating the underlying biological processes through which exogenous sex steroids influence the pathogenesis of asthma in women

Learn More – Primary Sources:

Hormonal contraception and the risk of severe asthma exacerbation: 17-year population-based cohort study

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