title: Nocturnal emergency department visits, duration of symptoms and risk of hospitalisation among adults with asthma exacerbations: a multicentre observational study.
abstract: We sought to compare the characteristics of patients with asthma presenting to the emergency department (ED) during the night-time with those of patients presenting at other times of the day, and to determine whether the time of ED presentation is associated with the risk of hospitalisation.
  
  
  
  A multicentre chart review study of 23 EDs across Japan.
  
  
  
  Patients aged 18-54 years with a history of physician-diagnosed asthma, presented to the ED between January 2009 and December 2011 OUTCOME MEASURES: The outcome of interest was hospitalisation, including admissions to an observation unit, inpatient unit and intensive care unit.
  
  
  
  Among the 1354 patients (30.1% in the night-time group vs 69.9% in the other time group) included in this study, the median age was 34 years and ∼40% were male. Overall 145 patients (10.7%) were hospitalised. Patients in the night-time group were more likely to have a shorter duration of symptoms (≤3 hours) before ED presentation than those in the other time group (25.9% in night-time vs 13.4% in other times; p<0.001). In contrast, there were no significant differences in respiratory rate, initial peak expiratory flow or ED asthma treatment between the two groups (p>0.05). Similarly, the risk of hospitalisation did not differ between the two groups (11.3% in night-time vs 10.5% in other times; p=0.65). In a multivariable model adjusting for potential confounders, the risk of hospitalisation in the night-time group was not statistically different from the other time group (OR, 1.10; 95% CI 0.74 to 1.61; p=0.63).
  
  
  
  This multicentre study in Japan demonstrated no significant difference in the risk of hospitalisations according to the time of ED presentation.
authors: Intensive Care Unit, Department of Emergency and Critical Care Medicine, Japanese Red Cross Musashino Hospital, Tokyo, Japan Department of Intensive Care Medicine, Kaneda Medical Center, Chiba, Japan.
authors: Hideto
authors: H
authors: Yasuda
authors: Department of Pediatric Emergency and Critical Care Medicine, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
authors: Yusuke
authors: Y
authors: Hagiwara
authors: Department of Radiology, University of Washington, Seattle, Washington, USA.
authors: Hiroko
authors: H
authors: Watase
authors: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors: Kohei
authors: K
authors: Hasegawa
mesh_terms: D000293:Adolescent; D000328:Adult; D039602:After-Hours Care / Q000706:statistics & numerical data*; D001249:Asthma; D018450:Disease Progression; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012306:Risk; D013997:Time Factors; D055815:Young Adult
keywords: asthma exacerbation; emergency department; nocturnal asthma; nocturnal visits; symptoms