Incidence and Risk of Various Disorders of the External Ear in Patients With Hearing Aids Treated in ENT Practices in Germany Objective: The aim of the study was to investigate the relationship between the presence of a hearing aid (HA) and the occurrence of various disorders of the external ear, using data from ear, nose, and throat (ENT) practices in Germany from a nationwide, representative practice database. Methods: In the period between 2012 and 2016, the incidences of disorders of the external ear (ICD-10 groups H60 and H61) in patients with HA prescriptions were compared retrospectively with a control group without HA prescriptions (1:1 matching). Results: A total of 20,127 patients with HA prescriptions were compared with 20,127 controls. The highest 12-month incidences (HA vs. controls) were determined for “Impacted cerumen” (H61.2) (16.5% vs. 4.2%), “Unspecified otitis externa” (H60.9) (2.6% vs. 1.2%) and "Acute noninfective otitis externa" (H60.5) (2.3% vs. 0.7%). The most significant risk increases for HA wearers were found for “Abscess of external ear" (H60.0, OR 10.03), “Other otitis externa" (H60.8, OR 6.00), and “Impacted cerumen" (H61.2, OR 4.55). A smaller risk increase was found for “Cholesteatoma of external ear" (H60.4, OR 2.26), among others. Conclusion: In HA wearers, the risk of developing almost all of the diagnoses reviewed is significantly increased, especially for external auditory canal (EAC) furuncle, chronic otitis externa, and impacted cerumen. This study provides the first epidemiological evidence for HA as a risk factor for the rare EAC cholesteatoma. Address correspondence and reprint requests to Karel Kostev, Ph.D., D.M.Sc., Epidemiology IQVIA, Unterschweinstiege 2-14, 60549 Frankfurt am Main, Germany; E-mail: kkostev@de.imshealth.com Compliance with ethical guidelines: Under certain conditions, German law permits the use of anonymized electronic medical data for research purposes. According to this legislation, this type of observational study without identifiable patient data does not require consent or an ethics committee vote. The authors did not have access to identifiable patient data at any time during the study. There are no conflicts of interest. Copyright © 2019 by Otology & Neurotology, Inc. Image copyright © 2010 Wolters Kluwer Health/Anatomical Chart Company