title: Clinical course and outcome of patients enrolled in US and non-US centres in MADIT-CRT.
abstract: OBJECTIVE
  We aimed to evaluate within the MADIT-CRT database whether different enrollment characteristics between US and non-US centres affected the clinical course of study patients.
  
  
  RESULTS
  We evaluated differences in baseline characteristics, procedure-associated complications, clinical as well as echocardiographic response to cardiac resynchronization therapy with a defibrillator (CRT-D), between patients enrolled in 87 US centres (n = 1271) and 23 non-US centres (n = 549) in MADIT-CRT. Non-US patients displayed significant differences in baseline characteristics from US patients, including a higher frequency of left bundle branch block, a more advanced heart failure (HF) functional class >3 months prior to enrollment, and larger baseline cardiac volumes. Procedure-related complications occurred at a significantly higher frequency among patients enrolled in non-US centres (17%) than among those enrolled in US centres (10%; P < 0.001). During follow-up, CRT-D was associated with 42% (P = 0.003) and 38% (P < 0.001) reductions in the risk of HF or death in the two respective groups (P for the difference = 0.80), and with similar reductions in cardiac volumes (all P > 0.10). Subgroup analysis showed a more pronounced effect of CRT-D among women in the US group, including a significant 71% (P = 0.02) reduction in the risk of death, whereas CRT-D therapy was associated with a significant clinical benefit in men only in the non-US group.
  
  
  CONCLUSIONS
  Patients enrolled in US and non-US centres in MADIT-CRT displayed significant differences in baseline clinical and echocardiographic characteristics and in the frequency of procedure-related complications, but experienced an overall similar clinical and echocardiographic response to CRT-D.
authors.affiliation: The Leviev Heart Center, Heart Institute, Sheba Medical Center, Tel Hashomer, Ramat-Gan 52621, Israel. yonibuber@gmail.com
authors.forename: Jonathan
authors.initials: J
authors.lastname: Buber
authors.forename: Helmut
authors.initials: H
authors.lastname: Klein
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Michael
authors.initials: M
authors.lastname: Eldar
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.forename: Juergen
authors.initials: J
authors.lastname: Vogt
authors.forename: Mathias
authors.initials: M
authors.lastname: Meine
authors.forename: Mary W
authors.initials: MW
authors.lastname: Brown
authors.forename: Alon
authors.initials: A
authors.lastname: Barsheshet
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
mesh_terms: D000328:Adult; D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000592:standards* / Q000706:statistics & numerical data; D003325:Coronary Care Units / Q000706:statistics & numerical data*; D017147:Defibrillators, Implantable / Q000009:adverse effects / Q000592:standards* / Q000706:statistics & numerical data; D004452:Echocardiography / Q000706:statistics & numerical data; D005060:Europe; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D007557:Israel; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data*; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult