Overall findings do not suggest that one medication within any of the classes evaluated is significantly more effective or harmful than the other medications within the same class, with the exception of zileuton being more harmful than the other LMs. Our results support the general clinical practice of starting initial treatment for persistent asthma with an ICS. For people with poorly controlled persistent asthma taking an ICS, our findings suggest that the addition of a LABA is most likely to provide the greatest benefit as the next step in treatment.