Malignant Otitis Externa: Is It Being Overdiagnosed?

Objectives: Malignant otitis externa (MOE), also known as necrotizing otitis externa or lateral skull base osteomyelitis (SBO), is an invasive and progressive infection of the external ear and lateral skull base. We use a large national database to better understand the epidemiology of current practice patterns of this rare clinical entity.

Materials and Methods: The Epic Cosmos database, a national HIPAA-defined limited electronic health record (EHR) dataset, was used to analyze a retrospective cohort of patients with an encounter including a diagnosis of malignant otitis externa between January 2010 and December 2023. Demographic information, pertinent medical history, all-cause mortality rate, antibiotic prescribing patterns, and rates of surgical intervention were collected.

Results: A total of 80,166 encounters involving 47,387 patients were included, comprising 0.72 per 100,000 encounters and 19.58 patients per 100,000 patients. A total of 25,500 (53.8%) were female. A total of 10,653 (13.3%) encounters were for pediatric patients and 69,401 (86.7%) encounters were for adult patients. Average age at encounter was 51.0 years (SD: 24.1), with average adult age of 57.4 years (SD 18.9) and average pediatric age of 9.4 years (SD: 4.6). A total of 6,382 (8.0%) of the encounters were inpatient encounters. All-cause mortality within the cohort was 5.1%. Risk factors included type 1 diabetes mellitus (1,952, 4.1%), type 2 diabetes mellitus (13,082, 27.6%), other diabetes mellitus (3,012, 6.4%), HIV (318, 0.7%), history of malignancy (5,485, 11.6%), and history of chemotherapy (1,514, 3.2%). The predominant antimicrobials associated with these encounters were topical, including ciprofloxacin/dexamethasone (17,225, 21.5%), ofloxacin (6,243, 7.8%), and acetic acid solutions (793, 1.0%). In addition to oral ciprofloxacin (8,261, 10.3%), a wide range of other oral antibiotics were used, including amoxicillin (3,510, 4.4%), amoxicillin-clavulanate (5,744, 7.2%), cephalexin (1,133, 1.4%), azithromycin (1,720, 2.1%). Intravenous antibiotics such as ampicillin-sulbactam (427, 0.5%), cefepime (2,531, 3.2%) and piperacillin-tazobactam (2,218, 2.8%) were less commonly utilized, as were antifungal agents. The most common antifungal medications were fluconazole (1,266, 1.6%), ketoconazole (216, 0.3%), and voriconazole (214, 0.3%). Rates of surgical intervention were low, with a total of 533 (0.7%) encounters associated with a procedure. The most commonly performed procedure was a biopsy of the external auditory canal (205, 0.3%), followed by complete mastoidectomy (114, 0.1%).

Conclusion: Just over half of the cohort had classical MOE risk factors compared with the 90% typically seen in the literature. It is unclear if there has been a change in the profile of MOE patients or if MOE is being improperly diagnosed within EHR systems. Additionally, 15% of encounters were associated with antibiotics that have poor coverage against the common causative organisms, further indicating incorrect diagnosis within the EHR or a need for more education regarding proper antibiotic management of this recalcitrant disease. Finally, this project illustrates a potential pitfall of utilizing the EHR for retrospective research.

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Artikel online veröffentlicht:
07. Februar 2025