A new treatment algorithm designed by Australian researchers helps reduce asthma exacerbations during pregnancy. The findings appear in an Article in this week's European Respiratory issue of The Lancet, written by Professor Peter Gibson and Heather Powell, Centre for Asthma and Respiratory Diseases, University of Newcastle and Hunter Medical Research Institute, Newcastle, NSW, Australia, and colleagues.
Asthma is the most common chronic medical disorder to complicate pregnancy, and both mothers and health professionals expect asthma to be controlled with minimum drug exposure to the developing fetus. Previous work has shown that corticosteroid treatment for asthma may be more effective when based on actual measures of airway inflammation, and one possible measure is the fraction of exhaled nitric oxide (FENO-a direct marker of inflammation). In this new work--the Managing Asthma in Pregnancy (MAP) study--the authors developed an improved FENO-based treatment algorithm and tested its applicability for the adjustment of therapy for asthma during pregnancy.
MAP assessed 220 pregnant, non-smoking women with asthma, who were randomly assigned, before 22 weeks' gestation, to treatment adjustment at monthly visits by an algorithm using clinical symptoms (control group) or FENO concentrations (active intervention group). 111 women were randomly assigned to the FENO group (100 completed) and 109 to the control group (103 completed). The exacerbation rate in the active intervention group was around half that found in the control group (0•29 vs 0•62 exacerbations per pregnancy).
The authors point out that reduction in exacerbation frequency was accompanied by important changes in maintenance asthma pharmacotherapy, including more frequent use of inhaled corticosteroid but at a lower total daily dose, and earlier introduction of second line drugs such as long-acting β2 agonists. Maintenance asthma pharmacotherapy based on symptoms alone leads to overtreatment (too high a dose of inhaled corticosteroids) for some people, and under-treatment (not enough people using inhaled corticosteroids) for others. The use of FENO identifies women with asymptomatic airway inflammation who are at risk of asthma exacerbation, and permits better tailoring of asthma therapy. The authors conclude: "Asthma management during pregnancy can be improved by the use of measuring FENO concentration, and symptoms to adjust treatment. This algorithmic approach might also be beneficial for non-pregnant women with asthma."
In a linked Comment, Dr Stanley J Szefler, Department of Pediatrics, National Jewish Health, Denver, CO, and University of Colorado School of Medicine, Denver, CO, USA, concludes: "These results lend support to the hypothesis that FENO-guided therapy for asthma in pregnancy could lead to beneficial fetal outcomes; however, this notion needs to be confirmed by further study. Future work should investigate the application of this algorithm in routine antenatal care and other settings."
Professor Peter Gibson, Centre for Asthma and Respiratory Diseases, University of Newcastle and Hunter Medical Research Institute, Newcastle, NSW, Australia. T +61 2 4985 5766 E) peter.gibson@hnehealth.nsw.gov.au
Dr Stanley J Szefler, Department of Pediatrics, National Jewish Health, Denver, CO, and University of Colorado School of Medicine, Denver, CO, USA. T) +1-303-398-1193 E) szeflers@njhealth.org
Journal
The Lancet