What do systematic reviews say?

LABA/ICS vs LTRA + ICS

LABA + ICS showed no clear difference in serious adverse events compared with LTRA + ICS (moderate certainty).

• Addition to inhaled corticosteroids of long‐acting beta₂‐agonists versus anti‐leukotrienes for chronic asthma 2014 · Cochrane Headline outcomes only
  RR 1.33 [0.99, 1.79]
  9 studies · 6288 participants
  Moderate