January/February 2024
Study provides valuable real-world data on sex differences in severe asthma
By Rebecca Jenkins
Women with severe asthma (SA) have worse symptoms, increased exacerbation rates and are more likely to be obese than their male counterparts, a large UK study finds.
Researchers said severe asthma was known to be more common in women, but it was vital to further understand the different characteristics associated with severe asthma in women to establish personalised care and help to focus future research on understanding the underlying mechanisms driving sex differences in the condition.
In this retrospective epidemiological study, the researchers analysed cohorts with severe asthma from two UK independent datasets spanning primary and secondary care to evaluate the different characteristics and treatment of men and women with severe asthma in a real world setting.
The study included 3679 patients (60.9% women) from the UK Severe Asthma Registry (UKSAR) and 18,369 patients (67.9% women) from the Optimum Patient Care Research Database (OPCRD).
Women were more likely to be symptomatic than men with increased Asthma Control Questionnaire-6 and Royal College of Physicians-3 Question scores, the researchers reported in Thorax.
However, they had a higher mean forced expiratory volume in 1 second per cent (FEV1% predicted) than their male counterparts with no significant difference in peak expiratory flow.
Although women had higher exacerbation rates than men, mean levels of type 2 biomarkers IgE and fractional exhaled nitric oxide (FeNO) were lower in women with no significant difference in blood eosinophils or biological therapy.
In other findings, there were more current smokers among women than men, and more depression and anxiety.
Women were less likely to be on maintenance oral corticosteroids, the datasets showed, but more likely to be obese.
Professor Christine Jenkins, Head of the Respiratory Group at The George Institute for Global Health and Professor of Respiratory Medicine at UNSW Sydney, said the research added valuable real-world information to the discussion about sex differences in severe asthma, with the finding on obesity of particular importance.
‘This association is becoming increasingly evident and is very relevant to treatment response and prevention,’ she told Medicine Today.
Cluster analysis studies had identified neutrophilic asthma with obesity as a distinct phenotype in women, noted Professor Jenkins.
Other studies had linked asthma with obesity in women with higher morbidity and a poorer response to inhaled corticosteroids, likely due to the presence of neutrophils, compared with nonobese asthma.
Based on these findings, Professor Jenkins said it was important to determine the airway inflammation type in obese women with asthma before starting treatment, with corticosteroids and biologics targeting type 2 asthma potentially less effective in this group.
‘Obesity is also increasingly being identified as having a strong association with incidence of new asthma in longitudinal studies,’ Professor Jenkins said.
There was scant information at present on whether weight loss could moderate the effect of obesity on asthma outcomes, but this was a crucial area for more research as a few studies showed a possible trend to there being a benefit, she added.