Using an epidemiological model to investigate unwarranted variation: the case of ventilation tubes for otitis media with effusion in England

Abstract

This version represents the final author accepted manuscript, after peer-review and subsequent edits, without publisher formatting and pagination. AbstractObjectives: To investigate unwarranted variation in ventilation tube (VT) insertions for otitis media with effusion (OME) in children in England. This procedure is known to be 'overused' from audits of care provided, as only one in three VT insertions conform to the appropriateness criteria by the National Institute for Health and Clinical Excellence (NICE); but audits cannot identify the scale of 'underuse': i.e. patients who would benefit but are not treated. Methods:To explore both 'underuse' and 'overuse' of VTs for OME we developed an epidemiological model based on: definitions of children with OME expected to benefit from VTs according to NICE guidance; epidemiological and clinical information from a systematic review; and expert judgement. A range of estimates was derived using MonteCarlo simulation and compared with the number of VTs actually provided in the NHS in 2010.Results: About 32,200 children in England would be expected to benefit from VTs for OME per year (between 20,411 and 45,231 with 90% certainty). The observed number of VTs for OME-associated diagnoses however was 16,824. Conclusions:The expected population capacity to benefit from VTs for OME based on NICE guidance appeared to exceed, by far, the number of VTs actually provided in the NHS. So, while there is known 'overuse', there also may be substantial 'underuse' of VTs for OME if NICE criteria were applied. Future investigations of unwarranted variation should therefore not only focus on patients who are treated, but consider potential to benefit at the population level.

Variation in Utilization and Need for Tympanostomy Tubes across England and New England

“…16 OME is usually transitory and the expected benefit from ear tubes depends on the time lapsed from onset of diagnosis to when treatment is considered. 2,20–25 Our epidemiological model unites two probabilities: age-specific incidence and the disease course of OME.…”

“…16,19 The U.S. AAP guidelines recommend consideration of tympanostomy surgery with a +20dB or greater threshold and the English guidelines recommend surgery for a +25dB or greater threshold. 1,17 Both guidelines also suggest tube insertion for children with additional risk factors.…”

“…16 Participants included experts in audiology, otolaryngology, general practice, and epidemiology, and were invited to validate the model’s components and overall accuracy. The group judged the model to be a judicious representation of the NICE care pathway and treatment process governing OME.…”

“…The group judged the model to be a judicious representation of the NICE care pathway and treatment process governing OME. The parameters 16 were used unchanged in this study.…”

“…However, using RAND – UCLA appropriateness criteria 7,8 and patient data from chart reviews, a significant majority of U.S. tympanostomy insertions were found to be inappropriate. For example, a key finding from a study of tympanostomy insertions in England 16 was the suggestion that there appeared to be both over- and under-treatment: i.e. operations were carried out on patients who were unlikely to benefit and not on patients for whom the benefit was likely.…”