While there is ample published literature highlighting global variance in the spectrum of organisms that cause endogenous endophthalmitis (EE), there has been a lack of publications on how EE presents within different regions of the United States (US).
Study Design
This retrospective cross-sectional analysis reviewed 2002–2014 data from the National Inpatient Sample, a core database within the Healthcare Cost and Utilization Project; ICD-9 codes were used to identify cases of EE within that timeframe. Numbers of cases with higher Elixhauser Comorbidity Index scores (ECI), which is used to quantify comorbidity burden, were also identified and stratified by geographic region to evaluate variation by location.
Outcomes
The South region contained the greatest percentage of EE cases (37.9%); 23.6% of cases occurred in the West region, 19.7% in the Midwest region, and 18.9% in the Northeast region. The highest average ECI was in the Midwest, and the greatest proportion of patients aged ≥80 years and the highest mortality rates were in the Northeast. Pars plana vitrectomy rates ranged from 12.1%–14.7%. The most common organism seen in the US overall was methicillin-sensitive Staphylococcus aureus. The second most common pathogens were Streptococcus spp. in the Northeast and Midwest, methicillin-resistant S. aureus in the South, and Candida in the West. Of note, the South had the lowest incidence of fungal endophthalmitis, which is counter to what has been reported in studies on global predilection of fungal infections in other warm climates.
Limitations
Some outcomes (e.g., high ECI) that were found to be more present in specific geographic locations may simply reflect the fact that some regions have higher rates of comorbidities such as metabolic syndrome or a greater percentage of elderly adults in their populations. The study also depends on coding and documentation accuracy, which can be variable.
Clinical Significance
Results from this study make the case for the use of broad-spectrum coverage to treat EE, along with the inclusion of antifungal coverage. Vitrectomy rates may reflect regional differences in practice patterns. The authors highlight that regional outcome disparities may relate to infrastructural issues, such as access to high-level ophthalmic diagnostics.
Financial Disclosures: Dr. Arthi Venkat discloses financial relationships with Apellis Pharmaceuticals and EyePoint (Consultant/Advisor).