Mortality of malignant otitis externa: A prevalence meta-analysis

Malignant otitis externa (MOE) is an aggressive infection of the external auditory canal and the underlying bony structures of the skull base. Predominantly caused by Pseudomonas, the treatment has shifted from surgical to medical, with antimicrobial therapy being primary, although surgical intervention may still be required. This review aims to provide global prevalence and mortality data on MOE to help institutions establish treatment benchmarks.

A systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Searches were completed in Scopus and PubMed Databases for articles on MOE mortality published between 1994 and 2022. Publications included data on MOE, mortality, and all genders.

A total of 22 studies involving 9,633 patients diagnosed with MOE were analyzed. The gender distribution was nearly equal, with 4,819 (50.1%) males and 4,814 (49.9%) females. The patients' ages ranged from 18 to 90 years, with a mean age of 70.3 years. The pooled period prevalence of mortality due to MOE was estimated to be 18% (95% confidence interval: 6-30%), highlighting a significant mortality risk in patients with this condition. Heterogeneity across the studies was high (I² = 99%, p < 0.001). Additionally, the prevalence of comorbidities was significant: 57.1% of patients were diabetic, 51% had hypertension, and other notable comorbidities included chronic pulmonary diseases (12.2%), liver disease (7.2%), and malignancies (3.4%). The most common microbiological cause was Pseudomonas aeruginosa (30%), followed by Staphylococcus aureus (10%). Surgical interventions were performed in 3.7% of cases, and cranial nerve involvement was reported in 9% of patients, primarily affecting the facial nerve (91%). Morbidity related to MOE was found to be 15.2%, and sepsis was a complication in 0.5% of cases. The results underscore the importance of addressing both comorbidities and mortality risks in managing MOE patients.

This review highlights a significant global mortality rate of 18% in patients with MOE, with comorbidities like diabetes and hypertension contributing to worse outcomes. Despite current treatment advancements, mortality and morbidity remain substantial, stressing the need for early diagnosis, targeted interventions, and improved management strategies to enhance patient survival and outcomes.