Cystic fibrosis mutation classes in pediatric otitis media - Fickle or faulty?

Recent data have challenged the historical paradigm that cystic fibrosis (CF) protects against otitis media (OM). These findings raised questions about the pathogenesis of this ostensible change. In this study our aim is to characterize acute OM (AOM) risk based on CF genotype.

A retrospective chart review was completed at a tertiary care pediatric hospital. Charts of 159 CF patients seen at our facility from 2010 to 2019 were reviewed. Data collected included demographics, AOM infections, cystic fibrosis transmembrane conductance regulator (CFTR) allele mutations, pulmonary exacerbations (PE), and pancreatic insufficiency (PI) status. Mutation alleles were divided into five classes based on CF guidelines, which were further classified as severe (classes I-III) or mild (classes IV-V).

54% of patients had at least one episode of AOM with a mean of 1.5 episodes of AOM (standard deviation = 2.3). 86% of patients had severe/severe (S/S) alleles and 14% had severe/mild (S/M). S/S patients had significantly more PE (p = .004) and increased rates of PI (p < .001). Of the 131 patients with S/S mutations, 57% had an episode of AOM while only 46% the 22 S/M patients had an AOM episode (p = .357).

To our knowledge this is the first report showing a clinical trend towards increased middle ear disease in patients with severe CFTR mutations. Future prospective studies will be powered to demonstrate whether this trend is statistically significant. Patients with S/S mutations not only have more severe clinical phenotypes but may have additional unexpected complications such as middle ear disease.