Otitis media (OM) continues to be one of the leading causes of medical consultations and the most frequent reason for antibiotic prescription and surgery in children in high-income countries.¹ The surgical procedures offered to children with recurrent or persistent OM are (1) insertion of grommets (ventilation tubes), (2) adenoidectomy and (3) a combination of the two. Two clinical conditions, although distinctly defined, are in fact closely related and can overlap. In young children, acute otitis media (AOM) is one of the most common causes of illness. AOM is defined as the presence of fluid in the middle ear with signs and symptoms of an acute infection.² Although many children have occasional AOM, an important group of children suffer from recurrent episodes, defined here as three or more AOM episodes in 6 months or four or more episodes in 1 year. These recurrent AOM episodes cause considerable distress to children and their parents, through frequent episodes of acute ear pain, fever and general illness. Children and parents experience sleepless nights and time is lost from nursery or school and from work.^3,4

Otitis media with effusion (OME, ‘glue ear’) is defined as the presence of fluid in the middle ear behind an intact tympanic membrane without signs and symptoms of an acute infection. It is most common in young children, with a bimodal peak around 2 and 5 years of age. In total, 80% of children will have had a least one episode of OME by the age of 10 years. The main symptom of OME is impaired hearing because the middle ear effusion causes a conductive hearing loss.²

Children with persistent OME are prone to recurrent AOM episodes, and after an AOM episode all children suffer from OME for some time. As such, children with recurrent AOM not only suffer pain and discomfort during the acute episodes, but also experience OME-related hearing difficulties that may impact on their language, behaviour and progress at school.⁵ It is known that the impact of recurrent AOM on a child’s quality of life is equivalent to that of chronic conditions such as asthma.^6,7

Although clear National Institute for Health and Care Excellence (NICE) guidance² is available for the use of grommets in subgroups of children with persistent OME, it is not the case for the use of adenoidectomy, either in persistent OME or in recurrent AOM. NICE suggests that clinicians should consider the possible benefits of adenoidectomy in children selected for grommets for OME who also suffer from coexisting respiratory symptoms. However, NICE² recognises a need for further studies documenting the effect of adenoidectomy, either alone or as an adjuvant to grommet insertion, in the management of recurrent or persistent OM in children. In particular, NICE identified a need for studies to identify any subgroups who might benefit more or less than others from surgical intervention. We know that adenoidectomy or adjuvant adenoidectomy is routinely performed in many countries for recurrent or persistent OM, but the concern of NICE² reflects the knowledge that the practice is not backed by high-quality scientific evidence.

The adenoid is an aggregate of lymphoid tissue located in the nasopharynx. With an extensive system of folds and crypts on its surface, the adenoid traps viruses and bacteria that pass through the upper airways. As part of the immune system, the adenoid plays an important role in the body’s immune response to infectious microorganisms that pass through the upper airways. Although many of these microorganisms may simply be transient passengers, the adenoid may serve as a reservoir for a diverse microbial community, resulting in upper respiratory infections. Because the adenoid lies next to the orifices of the Eustachian tubes, it has long been recognised as an important factor in the pathogenesis of OM. Microorganisms may spread via the Eustachian tube to the middle ear and cause acute, recurrent or chronic infections. Adenoidectomy is thought to improve middle ear function by removing or reducing the reservoir of opportunistic pathogens.⁸ A number of trials have studied the effect of adenoidectomy alone or of grommets with adjuvant adenoidectomy in children with OM.^9–25 Differences in the study design, population characteristics, outcomes measured and duration of follow-up, and particularly the use of small sample sizes, have made it difficult to come to any definite conclusions about the effects of adenoidectomy. It is possible – indeed likely – that both over- and undertreatment occurs. An individual patient data (IPD) meta-analysis, that is, a meta-analysis of the original individual data from previous trials, offers a unique opportunity to identify subgroups that may be more or less likely to benefit from adenoidectomy than others. Members of our group have successfully applied the IPD meta-analysis methodology to evaluate the effectiveness of antibiotics in children with acute OM and grommets in OME in specific subgroups.^26,27