Frequency with which outcome domains, and outcomes used to measure them, were selected in 115 trials involving only children published between 1988 and 2008.

Abbreviations used in Table 2: ACTH = adrenocorticotropic hormone; ADL = Activities of Daily Living; AE = adverse events; BHR = bronchial hyperresponsiveness; FEV1 = forced expiratory flow in one second; FVC = forced vital capacity; H-P-A = Hypothalamic-pituitary-adrenal; HRU = health resource utilisation; ICS = inhaled corticosteroids; IgE = Immunoglobulin E; PEFR = peak expiratory flow rate; QoL = Quality of life.aOf 84 studies that specified primary outcomes, 5 specified co-primary outcomes, and hence the total number of primary outcomes measured is 89.bLeukotriene LTC4 in serum and nasal secretions and leukotriene LTE4 in urine.cInterleukins in serum and sputum.dEosinophils in serum and sputum, and Eosinophil Cationic Protein in serum and urine.eIgE in serum.