title: The daily incidence of out-of-hospital cardiac arrest unexpectedly increases around New Year's Day in Japan.
abstract: BACKGROUND
  Over 100,000 patients are diagnosed every year as out-of-hospital cardiac arrest (OHCA) cases in Japan and their number has continued to rise for the last decade, presenting a challenge for preventive public health research as well as emergency medical care. The purpose of this study was to identify whether there are any temporal patterns in daily OHCA presentations in Japan.
  
  
  METHODS
  Records of OHCA patients (n=701,651) transported by ambulance over the course of six years (1st January 2005 to 10th March 2011) in Japan were obtained from the All-Japan Utstein registry data of cardiopulmonary arrest patients. Time periods within which the incidence of OHCA significantly increased were identified by a temporal cluster detection test using scan statistics. The risk ratios of OHCA for the detected periods were calculated and adjusted according to a Poisson regression model accounting for effects of other factors.
  
  
  RESULTS
  The risk of OHCA significantly rises 1.3-1.6 times around New Year's Day in Japan.
  
  
  CONCLUSIONS
  Our analysis revealed the increased daily incidence of OHCA around every New Year's Day in Japan.
authors: Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: kunihiko@med.nagoya-u.ac.jp.
authors: Kunihiko
authors: K
authors: Takahashi
authors: Centre for Biological Diversity and Scottish Oceans Institute, University of St Andrews, UK.
authors: Hideyasu
authors: H
authors: Shimadzu
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000706:statistics & numerical data*; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D058687:Out-of-Hospital Cardiac Arrest / Q000453:epidemiology* / Q000628:therapy; D012042:Registries; D012189:Retrospective Studies; D013997:Time Factors
keywords: Cardiac arrest; New Year's Day; Out-of-hospital; Temporal clustering; Time series