Objective In the past few decades, there has been an increase in high-quality studies providing evidence on the effectiveness of commonly performed procedures in paediatric otolaryngology. We... Show moreObjective In the past few decades, there has been an increase in high-quality studies providing evidence on the effectiveness of commonly performed procedures in paediatric otolaryngology. We believe that now is the time to re-evaluate the care process. We aimed to analyse (1) the regional variation in incidence and referrals of adenoidectomies, tonsillectomies and ventilation tube insertions in children in the Netherlands between 2016 and 2019, (2) whether regional surgical rates, referral rates and in-hospital surgical rates were associated with one another, and (3) the hospital variation in healthcare costs, which indicates the utilisation of resources. Design Repeated cross-sectional analysis. Setting Four neighbouring Dutch provinces comprising 2.8 million inhabitants and 14 hospitals. Participants Children aged 0-15 years. Outcome measures We analysed variation in regional surgical rates and referral rates per 1000 inhabitants and in-hospital surgical rates per 1000 clinic visitors, adjusted for age and socioeconomic status. Furthermore, the relationships between referral rates, regional surgical rates and in-hospital surgical rates were estimated. Lastly, variation in resource utilisation between hospitals was estimated. Results Adenoidectomy rates differed sixfold between regions. Twofold differences were observed for adenotonsillectomy rates, ventilation tube insertion rates and referral rates. Referral rates were negatively associated with in-hospital surgical rates for adenotonsillectomies, but not for adenoidectomies and ventilation tube insertions. In-hospital surgical rates were positively associated with regional rates for adenoidectomies and adenotonsillectomies. Significant variation between hospitals was observed in costs for all resources. Conclusions We observed low variation in tonsillectomies and ventilation tube insertion and high variation in adenoidectomies. Indications for a tonsillectomy and ventilation tube insertion are well defined in Dutch guidelines, whereas this is not the case for an adenoidectomy. Lack of agreement on indications can be expected and high-quality effectiveness research is required to improve evidence-based guidelines on this topic. Show less