title: Epidemiology and socioeconomic features of appendicitis in Taiwan: a 12-year population-based study.
abstract: BACKGROUND
  This paper presents an epidemiologic study of appendicitis in Taiwan over a twelve-year period. An analysis of the incidence in the low-income population (LIP) is included to explore the effects of lower socioeconomic status on appendicitis.
  
  
  METHODS
  We analyzed the epidemiological features of appendicitis in Taiwan using data from the National Health Insurance Research Database (NHIRD) from 2000 to 2011. All cases diagnosed as appendicitis were enrolled.
  
  
  RESULTS
  The overall incidences of appendicitis, primary appendectomy, and perforated appendicitis were 107.76, 101.58, and 27.20 per 100,000 per year, respectively. The highest incidence of appendicitis was found in persons aged 15 to 29 years; males had higher rates of appendicitis than females at all ages except for 70 years and older. Appendicitis rates were 11.76 % higher in the summer than in the winter months. A multilevel analysis with hierarchical linear modeling (HLM) revealed that male patients, younger patients (aged ≤14 years), and elderly patients (aged ≥60 years) had a higher risk of perforated appendicitis; among adults, the incidence increased with age. Moreover, the risk of perforation was higher in patients with one or more comorbidities. LIP patients comprised 1.25 % of the total number of patients with appendicitis from 2000 to 2011. The overall incidence of appendicitis was 34.99 % higher in the LIP than in the normal population (NP), and the incidence of perforated appendicitis was 40.40 % higher in the LIP than in the NP. After multivariate adjustment, the adjusted hospital costs and length of hospital stay (LOS) for the LIP patients were higher than those for the NP patients.
  
  
  CONCLUSIONS
  Appendicitis and appendectomy in Taiwan had similar overall incidences, seasonality patterns, and declining trends compared to numerous previous studies. Compared to NP patients, LIP patients had a higher risk of appendicitis, longer LOS and higher hospital costs as a result of appendectomy.
authors.affiliation: School of Computer & Information Engineering, Xiamen University of Technology, Xiamen, 361024 China.|Department of Computer Science and Engineering, Yuan Ze University, Taoyuan, 32003 Taiwan.
authors.forename: Kai-Biao
authors.initials: KB
authors.lastname: Lin
authors.affiliation: Department of Computer Science and Engineering, Yuan Ze University, Taoyuan, 32003 Taiwan.|Innovation Center for Big Data and Digital Convergence, Yuan Ze University, Taoyuan, 32003 Taiwan.
authors.forename: K Robert
authors.initials: KR
authors.lastname: Lai
authors.affiliation: Management Center, Keelung Hospital, Ministry of Health and Welfare, Keelung, 20147 Taiwan.|Institute of Public Health, National Yang-Ming University, Taipei, 11221 Taiwan.
authors.forename: Nan-Ping
authors.initials: NP
authors.lastname: Yang
authors.affiliation: Department of Information Management, Yuan Ze University, Taoyuan, 32003 Taiwan.|Innovation Center for Big Data and Digital Convergence, Yuan Ze University, Taoyuan, 32003 Taiwan.
authors.forename: Chien-Lung
authors.initials: CL
authors.lastname: Chan
authors.affiliation: Department of Computer Science and Engineering, Yuan Ze University, Taoyuan, 32003 Taiwan.|Innovation Center for Big Data and Digital Convergence, Yuan Ze University, Taoyuan, 32003 Taiwan.|Section of Cardiology, Cardiovascular Center, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Yuan-Hung
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Innovation Center for Big Data and Digital Convergence, Yuan Ze University, Taoyuan, 32003 Taiwan.
authors.forename: Ren-Hao
authors.initials: RH
authors.lastname: Pan
authors.affiliation: Department of Obstetrics & Gynecology, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan.
authors.forename: Chien-Hsun
authors.initials: CH
authors.lastname: Huang
keywords: Appendectomy; Appendicitis; Epidemiology; Socioeconomic status