title: The generalizability of observational data to elderly patients was dependent on the research question in a systematic review.
abstract: OBJECTIVE
  Despite the increasing use of data derived from randomized controlled trials (RCTs) to perform observational studies, little is known about the validity of this approach. We compared inferences from studies that were performed using Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) RCT data with those derived from studies using data from the population-based Cooperative Cardiovascular Project (CCP).
  
  
  METHODS
  We performed a systematic review. Articles were included if similar study questions were addressed by at least one manuscript that used GUSTO data and one that used CCP data.
  
  
  RESULTS
  GUSTO findings were disparate from CCP data regarding absolute rates of specific process or outcome measures, such as thrombolysis-associated intracranial hemorrhage (ICH) (0.65% versus 1.43%, respectively), atrial fibrillation (10% versus 21%, respectively), or use of beta-blockers (58% versus 37%, respectively). However, many important relations noted in GUSTO were corroborated by studies using CCP data. Both data sets identified similar predictors of ICH and presentation delay. The degree of variability in beta-blocker use (across geographic region) and angiography use (between genders) was remarkably similar when studied using CCP or GUSTO data.
  
  
  CONCLUSIONS
  Inferences derived from GUSTO about treatment variations and risk factors for outcomes were generalizable to community patients.
authors.affiliation: Section of General Internal Medicine, Department of Medicine, Yale-New Haven Hospital Center for Outcomes Research and Evaluation, 20 York St., New Haven, CT 06504, USA. cary.gross@yale.edu
authors.forename: Cary P
authors.initials: CP
authors.lastname: Gross
authors.forename: Pushkal P
authors.initials: PP
authors.lastname: Garg
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000706:statistics & numerical data; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000517:prevention & control; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D013300:Streptokinase / Q000627:therapeutic use; D015912:Thrombolytic Therapy / Q000379:methods; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use
chemical_list: D013300:Streptokinase; D010959:Tissue Plasminogen Activator