Interaction Effects between COVID-19 Outbreak and Community Income Levels on Excess Mortality among Patients Visiting Emergency Departments

Abstract

Background The objective of this study was to examine the effect of the coronavirus disease 2019 (COVID-19) outbreak on excess in-hospital mortality among patients who visited emergency departments (EDs) and to assess whether the excess mortality during the COVID-19 pandemic varies by community income level. Methods This is a cross-sectional study using the National Emergency Department Information System (NEDIS) database in Korea. The study population was defined as patients who visited all 402 EDs with medical conditions other than injuries between January 27 and May 31, 2020 (after-COVID) and for the corresponding time period in 2019 (before-COVID). The primary outcome was in-hospital mortality. The main exposure was the COVID-19 outbreak, and the interaction variable was county per capita income tax. We calculated the risk-adjusted in-hospital mortality rates by COVID-19 outbreak, as well as the difference-in-difference of risk-adjusted rates between the before-COVID and after-COVID groups according to the county income tax using a multilevel linear regression model with the interaction term. Results A total of 11,662,167 patients (6,765,717 in before-COVID and 4,896,450 in after-COVID) were included in the study with a 1.6% crude in-hospital mortality rate. The risk-adjusted mortality rate in the after-COVID group was higher than that in the before-COVID group (1.82% vs. 1.50%, difference: 0.31% [0.30 to 0.33]; adjusted odds ratio: 1.22 [1.18 to 1.25]). The excess in-hospital mortality rate of the after-COVID in the lowest quartile group of county income tax was significantly higher than that in the highest quartile group (difference-in-difference: 0.18% (0.14 to 0.23); P -for-interaction: < 0.01). Conclusion During the COVID-19 pandemic, there was excess in-hospital mortality among patients who visited EDs, and there were disparities in excess mortality depending on community socioeconomic positions.

Suicide attempt-related emergency department visits among adolescents: a nationwide population-based study in Korea, 2016–2019

“…During the study period from 2016 to 2019, the participation rate of nationwide EDs in the NEDIS was 408 of 413 (98.8%) EDs in 2016, 413 of 416 (99.3%) EDs in 2017, 399 of 401 (99.5%) EDs in 2018, and 401 of 402 (99.8%) EDs in 2019. The detailed design and variables of the NEDIS database have been described elsewhere [ 23 – 25 ].…”

Association between time to emergency neurosurgery and clinical outcomes for spontaneous hemorrhagic stroke: A nationwide observational study

“…Inaccurate data is filtered by a data processing system. The NEDIS data is updated in real time by the National Emergency Medical Center and approved annually by National Statistics for data quality management [ 13 , 14 ].…”

Aggressiveness of care in the last days of life in the emergency department of a tertiary hospital in Korea

“…It may be due to general hesitancy or ED transport refusal among patients [ 43 , 44 ] and limited resources under new policies [ 24 ]. Although there were no significant differences in disease-related ED mortality by year, the increasing number of total deaths, length of stay, and proportion of patients with KTAS levels 1–2 is in line with worsening mortality in Korea which is affected by the collateral damage of COVID-19 [ 25 ]. Our finding that 63.5% of ED visitors had cancer supports a Taiwanese study that reported cancer patients visited EDs more frequently near EOL, possibly due to high national health insurance coverage [ 45 ].…”

“…Furthermore, the coronavirus disease of 2019 (COVID-19) pandemic has also imposed strict quarantine policies such as large-scale screening for viral symptoms and visitor restrictions [ 18 ], thus making the ED more unsuitable for death [ 19 , 20 ]. Although the total number of ED visitations decreased during the pandemic in the United States [ 21 , 22 ] and Korea [ 23 , 24 ], the ED mortality rate significantly increased after COVID-19 in Korea [ 25 ]. Hence, there is growing interest in providing and even initiating palliative care for terminal patients in ED [ 26 – 30 ].…”