title: The Risk Score Profile: a novel approach to characterising the risk of populations enrolled in clinical studies.
abstract: OBJECTIVE
  Interpreting the results and practice implications of clinical studies requires accurate characterisation of the baseline risk of the population. We evaluated the Thrombolysis in Myocardial Infarction (TIMI) risk score for STEMI as a tool to describe and compare the risk profile of populations enrolled in three clinical trials (InTIME-II, ASSENT-2 and MAGIC) and the National Registry of Myocardial Infarction.
  
  
  RESULTS
  The risk score was calculated for each patient (N=121,085) and the frequency distribution plotted for each population. The Risk Score Profiles were compared using the Kolmogorov-Smirnov test. The Risk Score Profile demonstrated a striking concordance between the baseline risk of patients in InTIME-II and ASSENT-2 (median scores in each= 3[1,4], P=0.11). In contrast, the distributions in MAGIC (designed to enroll high risk) and NRMI (registry) were shifted significantly toward higher risk (median scores=4[3,5] for MAGIC and 4[2,6] in NRMI, P < 0.0001 for each vs. InTIME-II). A graded relationship between the risk score and mortality was evident in each study (P<0.0001).
  
  
  CONCLUSIONS
  The frequency distribution of the TIMI Risk Score, or similar tools for risk assessment, may be used to quantify and readily compare the risk profile of populations enrolled in clinical studies.
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. dmorrow@partners.org
authors.forename: David A
authors.initials: DA
authors.lastname: Morrow
authors.forename: Elliott M
authors.initials: EM
authors.lastname: Antman
authors.forename: Sabina A
authors.initials: SA
authors.lastname: Murphy
authors.forename: Susan F
authors.initials: SF
authors.lastname: Assmann
authors.forename: Robert P
authors.initials: RP
authors.lastname: Giugliano
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Cannon
authors.forename: C
authors.initials: C
authors.lastname: Michael Gibson
authors.forename: Carolyn H
authors.initials: CH
authors.lastname: McCabe
authors.forename: Hal V
authors.initials: HV
authors.lastname: Barron
authors.forename: Frans
authors.initials: F
authors.lastname: Van De Werf
authors.forename: Eugene
authors.initials: E
authors.lastname: Braunwald
mesh_terms: D000368:Aged; D003627:Data Interpretation, Statistical; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D015912:Thrombolytic Therapy / Q000379:methods*
chemical_list: D005343:Fibrinolytic Agents