RESUMEN
OBJECTIVE: To assess the efficacy and safety profile of tiotropium when added to low- to medium-dose inhaled corticosteroid (ICS) regimen versus low- to medium-dose ICS alone for adults with mild to moderate uncontrolled persistent asthma. DATA SOURCES: The online databases Pubmed, Embase and the Cochrane Library were searched for relevant data published up to November 14, 2017; we also conducted a supplementary search using clinicaltrials.gov. STUDY SELECTIONS: Only randomized control trials were included in this review. RESULTS: Four studies met our inclusion criteria for this review. In our review, two crossover studies were rated as "high risk" in the domain of "other bias" because a washout was not performed between each intervention. Lung function was significantly improved in the patient group receiving low- to medium-dose ICS with tiotropium. Results were consistent between each of three subgroups (tiotropium dry powder inhaler 18 µg or Respimat Soft Mist inhaler 5 µg, Respimat Soft Mist inhaler 2.5 µg, and Respimat Soft Mist inhaler 1.25 µg). Although no significant difference in Asthma Control Questionnaire (ACQ) score was found between the two treatment groups, substantial heterogeneity was observed. The incidence of serious adverse events between the two treatment groups was not statistically significant. CONCLUSIONS: Tiotropium as a once daily add-on to low- to medium-dose ICS may be efficacious and well-tolerated treatment in adults with moderate uncontrolled asthma. However, as only a few studies were identified, more studies of better design and long-term trial duration are required in the future.