title: Early β-blocker use and in-hospital mortality in patients with Takotsubo cardiomyopathy.
abstract: A catecholamine-mediated mechanism has been implicated in the pathogenesis of Takotsubo cardiomyopathy (TC). However, the impact of β-blockers in acute-phase management of TC remains uncertain. This study aimed to examine whether early β-blocker use in TC was associated with lower in-hospital mortality.
  
  
  
  This was a retrospective cohort study using the Diagnosis Procedure Combination nationwide inpatient database in Japan. Patients with TC aged ≥20 years who were admitted to acute-care hospitals between 2010 and 2014 were identified. Thirty-day in-hospital mortality was compared between patients who started β-blocker therapy on hospitalisation day 1 or 2 (early β-blocker group) and those who did not receive a β-blocker during hospitalisation (control group) using propensity score-matching and instrumental variable analyses.
  
  
  
  Of 2672 eligible patients (female, 81.5%; 423 early β-blocker therapy, 2249 controls) from 615 hospitals, 1:4 propensity score-matching created a cohort of 2110 patients (422 early β-blocker therapy, 1688 controls). There was no significant difference in 30-day in-hospital mortality between the early β-blocker group and control group (2.4% vs 2.0%, p=0.703; risk difference, 0.4%; 95% CI, -1.2% to 2.0%). Logistic regression analysis did not show a significant association between early β-blocker use and 30-day in-hospital mortality (OR, 1.17; 95% CI 0.58 to 2.37). Instrumental variable analysis also found that early β-blocker use was not associated with lower 30-day in-hospital mortality (risk difference, 1.2%; 95% CI -3.1% to 5.5%).
  
  
  
  This study found no significant association between early β-blocker use and in-hospital mortality in patients with TC.
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan Department of Cardiology, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Isogai
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Department of Cardiology, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Health Policy and Informatics, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fushimi
authors.affiliation: Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D004334:Drug Administration Schedule; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012189:Retrospective Studies; D054549:Takotsubo Cardiomyopathy / Q000188:drug therapy* / Q000401:mortality
chemical_list: D000319:Adrenergic beta-Antagonists