title: Cardiac rehabilitation outcomes: impact of comorbidities and age.
abstract: OBJECTIVE
  Medical comorbidities (CM) contribute to cardiac rehabilitation (CR) underutilization. Whether individuals with coronary heart disease and an increased CM burden achieve similar benefits from CR as those with a low CM burden is unknown.
  
  
  METHODS
  We analyzed 794 patients with coronary heart disease completing CR from 1/96 to 4/08. Medical CM burden was assessed using a comorbidity index (CMI) previously validated in a CR population. Distance achieved on a 6-minute walk test, body mass index, and the physical and mental component scores on the Medical Outcomes Short Form 36 were measured at baseline and at CR completion. We performed multivariable linear regression to compare changes in these parameters between individuals with a low CM burden (CMI = 0) and those with a moderate (CMI = 1-2) or high (CMI > 2) CM burden by age group (<56, 56-65, and >65 years of age).
  
  
  RESULTS
  Mean age was 61.6 ± 10.6 years, 29% were women, 31% nonwhite; 305 individuals had a CMI = 0, 305 had a CMI = 1 to 2, and 184 had a CMI > 2. All subgroups, regardless of age or CMI, demonstrated improvements with CR on virtually all parameters measured. Among individuals younger than 56 years, those with a CMI = 0 had greater improvements in these parameters after multivariable adjustment than those with a CMI of 1 to 2 or more than 2. In contrast, in older age groups, the degree of improvement was similar regardless of CMI.
  
  
  CONCLUSIONS
  All patient groups, regardless of CM burden, benefited from CR. Medical CM burden, especially among older patients, should not discourage referral to CR.
authors.affiliation: University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Listerman
authors.forename: Vera
authors.initials: V
authors.lastname: Bittner
authors.forename: Bonnie K
authors.initials: BK
authors.lastname: Sanderson
authors.forename: Todd M
authors.initials: TM
authors.lastname: Brown
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015897:Comorbidity; D003327:Coronary Disease / Q000453:epidemiology* / Q000534:rehabilitation*; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016896:Treatment Outcome