One study  described no statistically significant difference in the number of USMA between montelukast and placebo (Fig. 4b, MD = −0.04, 95% CI −0.26 to 0.18). The other  showed no statistical significance in the number of patients presenting with at least one USMA (MD = −0.11, 95% CI −0.36 to 0.14). As outcome measures differed, the data could not be pooled.