title: Chronobiology of acute aortic rupture or dissection: a systematic review and a meta-analysis of the literature.
abstract: OBJECTIVE
  Identification and quantification higher risk incidence of aortic rupture or dissection (AARD) could be of clinical interest and improve preventive strategies.
  
  
  BACKGROUND
  Several studies and subsequent meta-analyses have shown chronobiologic variations in the timing of occurrence of myocardial infarction, stroke, and pulmonary embolism. Conversely, such evidences are currently lacking for AARD despite a number of studies available dealing with periodicity.
  
  
  METHODS
  MEDLINE, EMBASE, and Google Scholar databases were searched up to July 2013. Temporal variation in the incidence of AARD was analyzed including all studies analyzing seasonal, monthly, weekly, and circadian aggregations. Two authors independently reviewed and extracted data.
  
  
  RESULTS
  Forty-two studies for a total of more than 80 000 patients were included. Our results showed a significantly increased incidence of AARD in Winter (Chi-square 854.92, p < 0.001), with a relative risk (RR) of 1.171 (99% CI 1.169, 1.172), in December (Chi-square 361.03, p < 0.001), RR of 1.142 (99% CI 1.141, 1.143), on Monday (Chi-square 428.09, p < 0.001), RR of 1.214 (99% CI 1.211, 1.216), and in the hours between 6 am and 12 pm (Chi-square 212.02, p < 0.001), RR of 1.585 (99% CI 1.562, 1.609). Subgroup and sensitivity analyses confirmed the results of principal analyses.
  
  
  CONCLUSIONS
  Our data strongly support the presence of evident rhythmic patterns in the incidence of acute aortic events, characterized by significantly higher risk in Winter, in December, on Monday and between 6 am and 12 pm. Future studies are needed to better clarify the underlying mechanisms and clinical implications.
authors.affiliation: Department of Clinical Medicine, University of Insubria , Varese , Italy .
authors.forename: Josè
authors.initials: J
authors.lastname: Vitale
authors.forename: Roberto
authors.initials: R
authors.lastname: Manfredini
authors.forename: Massimo
authors.initials: M
authors.lastname: Gallerani
authors.forename: Nicola
authors.initials: N
authors.lastname: Mumoli
authors.forename: Kim A
authors.initials: KA
authors.lastname: Eagle
authors.forename: Walter
authors.initials: W
authors.lastname: Ageno
authors.forename: Francesco
authors.initials: F
authors.lastname: Dentali
mesh_terms: D000208:Acute Disease; D001019:Aortic Rupture / Q000453:epidemiology*; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D015994:Incidence; D010507:Periodicity; D012621:Seasons
keywords: Aortic aneurysm; aortic rupture; chronobiology; circadian rhythm; dissection