title: Relationship between hospital volume and early outcomes in acute ischemic stroke patients treated with recombinant tissue plasminogen activator.
abstract: BACKGROUND
  There is controversy whether the annual number of acute ischemic stroke patients receiving stroke thrombolysis per hospital (hospital volume) is associated with outcomes in these patients.
  
  
  OBJECTIVE
  The study aims to assess the relationship between hospital volume and early outcomes in acute ischemic stroke patients treated with recombinant tissue plasminogen activator.
  
  
  METHODS
  Patients with acute ischemic stroke treated with recombinant tissue plasminogen activator from July 1, 2010 to March 31, 2012 were identified in the Japanese Diagnosis Procedure Combination database. Hospital volume was categorized into three levels (low, medium, and high volume) to obtain approximately equal numbers of patients in each group. Primary outcomes were seven-day mortality and functional independence (modified Rankin Scale score of 0 to 2) at discharge. Univariate analyses and multivariate logistic regression analyses fitted with generalized estimating equations were performed.
  
  
  RESULTS
  We identified 7476 eligible patients, including 2339 (31·3%) treated in low-volume hospitals (1-7 patients annually), 2670 (35·7%) in medium-volume hospitals (8-16 patients annually), and 2467 (33·0%) in high-volume hospitals (17-48 patients annually). Seven-day mortality and functional independence at discharge were comparable among the three hospital volume groups (P = 0·17 for seven-day mortality; P = 0·22 for functional independence at discharge). The comparability between groups persisted after multivariate adjustment.
  
  
  CONCLUSIONS
  Hospital volume was not significantly associated with seven-day mortality or functional independence at discharge in acute ischemic stroke patients treated with recombinant tissue plasminogen activator in Japan.
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Tokyo, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Wada
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
authors.forename: Ryota
authors.initials: R
authors.lastname: Inokuchi
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Horiguchi
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fushimi
authors.forename: Takehiro
authors.initials: T
authors.lastname: Matsubara
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakajima
authors.forename: Naoki
authors.initials: N
authors.lastname: Yahagi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000188:drug therapy* / Q000401:mortality; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: hospital volume; ischemic stroke; population-based study; recombinant tissue plasminogen activator; stroke facilities; thrombolysis