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2 "Chulyong Park"
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COVID-19: Original Article
Analyzing the dynamics of complicated and uncomplicated appendicitis during the COVID-19 pandemic in Seoul, Korea: a multifaceted time series approach
Kiook Baek, Chulyong Park
Epidemiol Health. 2024;46:e2024081.   Published online October 1, 2024
DOI: https://doi.org/10.4178/epih.e2024081
  • 833 View
  • 38 Download
AbstractAbstract AbstractSummary PDF
Abstract
OBJECTIVES
This study investigated the impact of the coronavirus disease 2019 (COVID-19) pandemic and associated control strategies on the incidence of appendicitis in Seoul, using data from 2018 to 2020 from Korea’s National Health Insurance.
METHODS
We analyzed records of total, complicated, and uncomplicated appendicitis cases, as well as the ratio of complicated to uncomplicated appendicitis, using natural spline and piecewise regression models to identify trends and breakpoints. Bayesian structural time-series (BSTS) models were used to evaluate the causal impact of social distancing on appendicitis incidences.
RESULTS
The spline regression analysis indicated decreasing trends in both total and uncomplicated appendicitis cases. Conversely, the incidence of complicated appendicitis and the ratio of complicated to uncomplicated cases increased. Breakpoints for a decline in uncomplicated appendicitis and a rise in the ratio occurred at 31 weeks in 2020 (95% confidence interval [CI], 23.2 to 38.8) and at 33.9 weeks (95% CI, 28.3 to 39.6), respectively. The BSTS model demonstrated a 7.8% reduction in total appendicitis cases (95% credible interval [CrI], -12.1 to -3.3). It also showed a 17.4% decrease in uncomplicated cases (95% CrI, -22.2 to -12.3) and increases of 12.8% (95% CrI, 4.9 to 22.0) in complicated cases and 39.0% (95% CrI, 27.0 to 53.3) in the ratio of complicated to uncomplicated appendicitis.
CONCLUSIONS
The COVID-19 pandemic resulted in a decrease in both total and uncomplicated appendicitis cases, while the number of complicated cases increased. Reduced medical visits likely accounted for these changes. Strategies are needed to manage changes in disease pathophysiology resulting from altered healthcare utilization during health crises.
Summary
Korean summary
-여러 연구에서 COVID-19 유행기간에 급성 충수염의 역학에 대한 변화가 있었다는 보고가 있어 국내 건강보험 청구 자료를 사용하여 확인하고자 하였다. -시계열 데이터로 역학의 변동 시점에 대한 분석을 수행한 결과, 유의미한 합병증이 없는 충수염의 감소와, 합병증을 동반한 충수염의 비율 변동이 시작된 시점은 사회적 거리두기를 한 시점과 유사한 것으로 나타났다. -사회적 거리두기를 한 시점 전후의 급성 충수염 역학을 비교하였을 때, 총 급성 충수염 및 합병증이 없는 충수염은 감소하는 경향이, 합병증을 동반한 충수염은 증가하는 경향이 유의하게 보였다.
Key Message
Several studies have reported changes in the epidemiology of acute appendicitis during the COVID-19 pandemic; this study aimed to confirm these findings using national health insurance claims data. Time-series analysis of the epidemiological shift points showed that the decrease in uncomplicated appendicitis cases and the shift in the proportion of complicated appendicitis cases occurred around the time social distancing measures were implemented. When comparing the epidemiology of acute appendicitis before and after the onset of social distancing, there was a significant decrease in the incidence of total acute appendicitis and uncomplicated cases, with a significant increase in complicated appendicitis cases.
Epidemiologic Investigation
An outbreak of neurologic symptoms among patients exposed to an unknown stench in a high school near an industrial complex: an epidemiological investigation
Kiook Baek, Seongmin Jo, Chulyong Park, Joon Sakong
Epidemiol Health. 2022;44:e2022105.   Published online November 9, 2022
DOI: https://doi.org/10.4178/epih.e2022105
  • 5,236 View
  • 107 Download
AbstractAbstract AbstractSummary PDFSupplementary Material
Abstract
OBJECTIVES
Seven students at a high school in Korea visited the emergency room with non-specific neurological symptoms after a stench was noticed during a school entrance ceremony. In relation to this incident, 105 patients visited medical institutions over 5 days. A team of environmental and epidemiological experts was assembled to investigate the incident.
METHODS
Our team of experts participated in the investigation 1 month post-incident. Previously, only air samples had been analyzed. We received results of air samples analyzed by other investigators, medical records of some students, and data from police interviews of patients. Additional investigation and interviews were conducted, and the events were reconstructed in spatial and temporal order.
RESULTS
A cluster of patients was observed on the south side and parts of the north side of the upper floor. A stench like that reported during the incident had been noticed for about 2 years near the school. Students consistently described a similar stench occurring frequently in the vicinity of the school. According to student statements, the odor mainly resembled something burning. The carboxyhemoglobin levels of some students were observed to be >1.5%.
CONCLUSIONS
In the investigation, 2 suspected sources were identified: a science room storing chemicals downstairs from the auditorium and various industrial facilities near the school. Combining the scattered evidence, we considered a toxic puff of gas, perhaps from brief incineration or leakage in a specific area, to be the likely cause of the incident. We describe our approach and the limitations encountered during the investigation.
Summary
Korean summary
본 논문은 일개 고등학교에서 원인미상의 악취와 함께 100명 이상의 환자가 발생한 사건에 대한 조사과정을 담은 문헌이다. 본 연구진은 사건 발생 후 약 1달 후에 조사진에 합류하였으며, 발생 당시 환자 분포 점지도 작성, 인근 지역 사업장 및 악취발생 장소 점지도 작성, 사건 전후 시계열적 사건분석, 기상자료, 관계자 인터뷰 자료 분석 등의 역학적 기법을 동원하여 원인을 인근 지역에서 발생한 퍼프 가스의 유입으로 추정하였다. 본 사건의 원인은 결국 미제로 종결되었지만 추후 유사 사례 발생시 본 조사의 방법론을 참고할 수 있을 것이며, 의료진의 조기 개입을 수행하지 못함으로 인한 초기 상세 인터뷰 자료 확보, 생체 시료 수집 등이 이루어지지 못한 본 조사 과정의 한계점을 반면교사로 삼을 수 있을 것이다.
Key Message
This paper presents an investigation of an outbreak of over 100 patients experiencing an unexplained odor in a high school. The research team utilized epidemiological methods, including dot mapping, temporal analysis of events, and interview data analysis. The source of the odor was estimated to be the inflow of puff gas from surrounding areas. Although the toxic puff gas discharge facility was not identified, sharing the experience from this investigation could help with future investigations of similar incidents.

Epidemiol Health : Epidemiology and Health
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