So asthma sufferers seem to lose out twice over. In the first place it is bad for them to have acid reflux, and in the second place they have acid reflux more often than other people. But this is not the whole story. If acid reflux was really an important cause of asthma worsening, then treatments against acid reflux should make the asthma better. In practice many doctors have found such treatment disappointing.
Research continues, but it's already continued a long time now.
It's hard to think we'll be surprised by future research on this. In the meantime, if you have asthma and you also have acid reflux, it could just be that careful treatment of your reflux will make your breathing better. If your asthma is bad and no-one knows why, some doctors would check whether you had reflux by getting an expert to measure the acidity in your gullet. If the result showed acid, they would try to improve your lungs by treating your stomach. If it was me, despite the reservations, I'd give it a try.