Emergency Department Presentations of Acute Primary Angle Closure in the United States from 2008 to 2017.

Purpose: Acute primary angle closure (APAC) is an ophthalmologic emergency. Nationwide data on the epidemiology and clinical characteristics of APAC are lacking despite the associated visual morbidity. Patients and Methods: A retrospective cross-sectional study using the Nationwide Emergency Department Sample (NEDS). The NEDS was queried by ICD-9/10 code for cases of APAC presenting to the United States emergency departments over a ten-year period from 2008 to 2017. All identified cases were included to produce nationally representative estimates. Linear regression and seasonality tests were used to identify trends. Reported outcomes include the incidence, demographics, seasonality, and economic impact of APAC regionally and nationwide. Results: A total of 23,203 APAC-related ED visits were identified. The mean (SD) and median ages were 58.8 (16.2) and 60 years, respectively. Females (59.4%, p < 0.01), those in the lowest income quartile (6983, 30.1%, p < 0.01), and those in the seventh decade of life (5599, 24.1%) presented more frequently with APAC. The incidence of ED presentations within each age group rose with age and increased significantly over the study period (p < 0.01). The Northeast region had the highest average incidence (0.93 per 100,000 population). Significant seasonal variation was seen regionally and nationally (p < 0.01), with the highest average incidence in December and lowest in April. Median inflation adjusted charge per ED visit was $2496.10, and the total inflation adjusted charges equaled $101.5 million. Conclusion: The incidence of APAC-related ED visits continues to rise in the United States. High-risk groups include women, individuals of low socioeconomic status, and those between ages 50 and 70. Significant seasonal and regional trends were observed in ED presentations of APAC.