MONTREAL — Asthma patients who have comorbid gastroesophageal reflux disease are able to improve their lung function by treating their acid reflux, Stephen K. Field, M.D., reported in a poster presentation at the 13th World Congress of Gastroenterology.
Patients with more severe asthma combined with nocturnal respiratory symptoms are the most likely to benefit, according to the study sponsored by AstraZeneca Pharmaceuticals.
“Clinicians should ask their asthma patients whether they have symptomatic reflux, and if they do, they should treat them like anyone who has symptomatic reflux,” said Dr. Field of the University of Calgary (Alta.).
Studies have shown that the prevalence of gastroesophageal reflux disease (GERD) is high in adults with asthma, and it has been speculated that reflux, particularly at night, may be an asthma trigger, Dr. Field said in an interview.
However, the reverse has also been suggested, namely that asthma might trigger GERD.
In this study, 770 patients with persistent, moderate to severe asthma and daily use of inhaled corticosteroids and/or leukotriene modifiers were randomized to receive esomeprazole (Nexium) 40 mg twice daily or placebo for 16 weeks.
The primary objective of the study was to assess the change in morning peak expiratory flow (PEF) from baseline to the end of treatment.
The participants were divided into three categories based on symptoms. One group had nocturnal respiratory symptoms but no GERD (201), one group had GERD but no nocturnal respiratory symptoms (219), and one group had both GERD and nocturnal respiratory symptoms (350).
Among the entire study population, morning PEF increased significantly more from baseline in patients treated with esomeprazole (22 L/min), compared with those who were treated with placebo (16 L/min).
This effect was most pronounced among the patients with both GERD and nocturnal respiratory symptoms.
However, no statistically significant differences were observed between the treatment groups or the symptom groups in terms of patient-reported forced expiratory volume in 1 second, asthma symptoms, or use of rescue medications.
The strongest treatment effect for esomeprazole was found in a subgroup of 307 patients who were taking both inhaled corticosteroids and long-acting β-agonists (suggesting more severe asthma).
In this group, the mean increase in both morning and evening PEF from baseline was significantly higher than it was among patients treated with placebo (26.1 L/min vs. 13.9 L/min for morning PEF, and 20.2 L/min vs. 9.1 L/min for evening PEF).
Again, within this subgroup of more severe asthma, the 119 patients reporting both GERD and nocturnal respiratory symptoms showed the most improvement in lung function with esomeprazole, with a change in morning PEF from baseline of 14.8 L/min, and evening PEF from baseline of 19 L/min. But once again, within this group of more severe asthma, esomeprazole resulted in no significant improvements in other asthma parameters.
The main weakness of the study is that those patients most likely to show an improvement with esomeprazole could not be included, said Dr. Field.
“You have to do what's ethically appropriate, so we had to exclude those with the worst reflux symptoms and those with erosive esophagitis because it would have been unethical to randomize them to possibly receive placebo.”
He said the study highlights the fact that GERD and asthma should be investigated simultaneously.
“Lots of patients with asthma have symptomatic GERD, but it's not something all clinicians ask their asthma patients about.”