Predicting omalizumab treatment response has been a challenge and significant aspect for selecting suitable severe allergic asthma patients for omalizumab use. To determine which domains of pretreatment baseline characteristics predict omalizumab treatment response among asthmatic patients. Electronic bases were searched for eligible studies that reported potential biomarkers that could predict omalizumab responsiveness and efficacy. Patients who accepted omalizumab treatment were stratified into responders and non-responders. WMD, OR, and their 95%CI were used to access the...