title: The Association Between Barium Examination and Subsequent Appendicitis: A Nationwide Population-Based Study.
abstract: OBJECTIVE
  The incidence and association between appendicitis and barium examination (BE) remain unclear. Such potential risk may be omitted. We conducted a longitudinal, nationwide, population-based cohort study to investigate the association between BE and appendicitis risk.
  
  
  METHODS
  From the Taiwan National Health Insurance Research Database, a total of 24,885 patients who underwent BE between January 1, 2000 and December 31, 2010 were enrolled in a BE cohort; an additional 98,384 subjects without BE exposure were selected as a non-BE cohort, matched by age, sex, and index date. The cumulative incidences of subsequent appendicitis in the BE and non-BE cohorts were assessed using the Kaplan-Meier curves and log-rank test. Cox proportional hazards regression analyses were employed to calculate the appendicitis risk between the groups.
  
  
  RESULTS
  The cumulative incidence of appendicitis was higher in the BE cohort than in the non-BE cohort (P = .001). The overall incidence rates of appendicitis for the BE and non-BE cohorts were 1.19 and 0.80 per 1000 person-years, respectively. After adjustment for sex, age, and comorbidities, the risk of appendicitis was higher in the BE cohort (adjusted hazard ratio = 1.46, 95% confidence interval = 1.23-1.73) compared with the non-BE cohort, especially in the first 2 months (adjusted hazard ratio = 9.72, 95% confidence interval = 4.65-20.3).
  
  
  CONCLUSIONS
  BE was associated with an increased, time-dependent appendicitis risk. Clinicians should be aware of this potential risk to avoid delayed diagnoses.
authors.affiliation: Department of Radiology, E-Da Hospital and I-Shou University, Kaohsiung, Taiwan.
authors.forename: Hao-Ming
authors.initials: HM
authors.lastname: Li
authors.affiliation: Department of Radiology, E-Da Hospital and I-Shou University, Kaohsiung, Taiwan.
authors.forename: Lee-Ren
authors.initials: LR
authors.lastname: Yeh
authors.affiliation: Department of Radiology, Kaohsiung Municipal Min-Sheng Hospital, Taiwan.
authors.forename: Ying-Kai
authors.initials: YK
authors.lastname: Huang
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan; College of Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Graduate Institute of Clinical Medical Science, School of Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan; Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan. Electronic address: d10040@mail.cmuh.org.tw.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001064:Appendicitis / Q000453:epidemiology / Q000209:etiology*; D001464:Barium / Q000009:adverse effects* / Q000627:therapeutic use; D003287:Contrast Media / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D041981:Gastrointestinal Tract / Q000000981:diagnostic imaging*; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011859:Radiography / Q000009:adverse effects / Q000379:methods; D012307:Risk Factors; D012737:Sex Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D003287:Contrast Media; D001464:Barium
keywords: Appendicitis; Barium; Epidemiology; Pathogenesis