What do systematic reviews say?

Combination inhaled therapy vs SABA

Combination inhaled therapy probably leads to lower relapse rates compared with SABA alone (moderate certainty).

• Combined inhaled beta‐agonist and anticholinergic agents for emergency management in adults with asthma 2017 · Cochrane Headline outcomes only
  RR 0.8 [0.66, 0.98]
  5 studies · 1180 participants
  Moderate