We wanted to perform subgroup analysis to check which patients were ‘montelukast responders’, especially checking if serum eosinophil or atopy predicted response. Unfortunately, there were insufficient data available to analyse this. Nwokoro et al.  did perform subgroup analysis and found that those patients with ALOX5 5/5 genotype had less USMA on montelukast compared with placebo, but there was some overlap between the groups. Repeatability in further large RCTs of such results would need to be performed for this to be convincing.