(851) Identification of prognostic predictors in patients with necrotizing otitis externa

Introduction: Necrotizing otitis externa (NOE) is a rare infectious disease with a heterogeneous clinical course, making prognostic prediction difficult. This study aimed to identify factors associated with prolonged hospitalization in patients with NOE.

Methods: We retrospectively reviewed 61 patients with NOE admitted between September 2009 and October 2024. Demographic characteristics, comorbidities, laboratory, microbiological, and radiological findings, as well as hospital stay duration, were analyzed. MRI assessed soft tissue involvement, skull base osteomyelitis, and white matter lesions using the Fazekas scale. Multivariable linear regression identified factors associated with length of hospital stay.

Results: Among 61 patients, 39 (63.9%) were male, with a mean age of 70.25 ± 13.11 years, and the average hospital stay was 46.02 ± 37.50 days. Diabetes mellitus was present in 75.4% of patients and chronic kidney disease in 25%, but neither diabetes nor HbA1c levels were significantly associated with hospital stay. However, patients with diabetic complications had significantly longer stays than those without (94.25 ± 63.17 vs. 38.74 ± 25.94 days, p < 0.001). Peak erythrocyte sedimentation rate (ESR) was significantly associated with prolonged hospitalization (p = 0.004). Pathogens were not identified in 37.7% of cases, while Pseudomonas aeruginosa and fungal infections were detected in 27.9% and 24.6%, respectively. Higher Fazekas scores on MRI were significantly associated with longer hospital stay and treatment duration (p = 0.018). Multivariable analysis showed that diabetic complications, peak ESR, and Fazekas scores were independent predictors of prolonged hospital stay (adjusted R² = 0.429).

Conclusions: Diabetic complications, peak ESR, and higher Fazekas scores were associated with longer hospitalization in necrotizing otitis externa, whereas diabetes status and HbA1c were not. These results suggest that vascular vulnerability may influence disease course and aid prognostic assessment and treatment planning.