title: Baseline risk has greater influence over behavioral attrition on the real-world clinical effectiveness of cardiac rehabilitation.
abstract: Few studies have examined the correlates of real-world cardiac rehabilitation (CR) effectiveness. The objective of this study was to determine the relationship between baseline risk, behavioral attrition, and the number needed to treat (NNT) associated with CR.
  
  
  
  A retrospective study was conducted among 16,061 CR patients between 1995 and 2011 in Canada. Multiple logistic regression models were derived from patient characteristics and measured baseline risk (individual's risk of death within 3 years) and behavioral attrition (individual's risk of premature dropout). We examined the treatment efficacy of CR among nondropouts using a 20% relative risk reduction. Further sensitivity analyses were performed to assess the robustness of our assumptions. We assumed no efficacy among dropouts.
  
  
  
  Both baseline risk and behavioral attrition were independently associated with NNT, although baseline risk had a stronger association with NNT than behavioral attrition. Increasing age, lower baseline fitness, history of diabetes, hypertension, and greater comorbidities were associated with lower NNT. Being female, living alone, living in the lowest neighborhood income quintile, and greater adiposity were associated with higher NNT.
  
  
  
  The clinical effectiveness of CR is largely driven by the baseline risk rather than the behavioral attrition of the populations they serve. These findings have implications for risk stratification among those with greatest survival yields and programmatic needs.
authors.affiliation: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, Suite 425, Toronto, Ontario M5T 3M6, Canada; Cardiovascular Prevention and Rehabilitation Program, University Health Network-Toronto Rehabilitation Institute, 347 Rumsey Road, Toronto, Ontario M4G 2V6, Canada.
authors.forename: Aviroop
authors.initials: A
authors.lastname: Biswas
authors.affiliation: Cardiovascular Prevention and Rehabilitation Program, University Health Network-Toronto Rehabilitation Institute, 347 Rumsey Road, Toronto, Ontario M4G 2V6, Canada.
authors.forename: Paul I
authors.initials: PI
authors.lastname: Oh
authors.affiliation: School of Kinesiology, University of British Columbia, 2146 Health Sciences Mall, Vancouver V6T 1Z3, Canada.
authors.forename: Guy E
authors.initials: GE
authors.lastname: Faulkner
authors.affiliation: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, Suite 425, Toronto, Ontario M5T 3M6, Canada; Cardiovascular Prevention and Rehabilitation Program, University Health Network-Toronto Rehabilitation Institute, 347 Rumsey Road, Toronto, Ontario M4G 2V6, Canada; Institute for Clinical Evaluative Sciences, G1-06, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada. Electronic address: dalter@ices.on.ca.
authors.forename: David A
authors.initials: DA
authors.lastname: Alter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D000072038:Cardiac Rehabilitation / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010352:Patient Dropouts / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cardiac rehabilitation; Clinical effectiveness; Myocardial infarction; Risk factors; Survival; Therapeutic evaluation