Prevalence of adenoid hypertrophy: A systematic review and meta-analysis

The purpose of our review was to synthesize the existing literature about the prevalence of adenoid hypertrophy (AH) in children and adolescents confirmed by the reference standard - the nasoendoscopy (NE). Six electronic databases and partial grey literature were searched. Studies were included if they reported the prevalence of AH confirmed via NE. Studies involving participants with associated comorbidities and/or fully diagnosed sleep apnea in their sample were excluded. The MAStARI tool assessed the potential risk of bias (RoB) among the studies, while the GRADE approach determined the level of evidence. A total of 5248 patients were included. Seventeen studies were included in the meta-analysis showing an AH prevalence of 49.70% (confidence interval (CI): 39.92 to 59.50). The studies were then divided into 3 groups based on the RoB assessment and patient selection method. The AH prevalence for group 1 (studies having low RoB) was 42.18% (CI: 34.93 to 49.60; n = 2794), for group 2 (studies having moderate RoB) was 70.02% (CI: 40.102 to 92.690; n = 538), and finally for group 3 (studies with randomly collected samples) was 34.46% (CI: 10.507 to 63.742; n = 1446). High heterogeneity between the studies was found. The GRADE approach classified the quality of evidence as moderate. In summary, in a randomized representative sample the prevalence of AH was 34.46%; however, in convenience samples the prevalence ranged from 42 to 70%.