title: The impact of comorbidity burden on the cardiovascular risk in the Peripheral Arteriopathy and Cardiovascular Events study.
abstract: BACKGROUND
  A comprehensive evaluation of comorbidity is important in predicting outcome of patients affected by a chronic disease because of the role of competing risk.
  
  
  OBJECTIVE
  To assess the prognostic impact of the Cumulative Illness Rating Scale (CIRS) on the cardiovascular risk of subjects participating in the Peripheral Arteriopathy and Cardiovascular Events (PACE) study.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  The study included 60 patients with peripheral arterial disease (PAD) and 163 no-PAD subjects. CIRS-illness severity (IS) score and CIRS-comorbidity index (CI) were calculated.
  
  
  RESULTS
  After a 42-month follow-up, 18/223 participants had a myocardial infarction or stroke. These subjects had a higher CIRS-IS score (1.99 +/- 0.52 vs. 1.71 +/- 0.37, P = 0.003) and a higher CIRS-CI (4.00 +/- 2.81 vs. 2.65 +/- 1.85, P = 0.005) vs. the 205 subjects without event. However, the significant association of CIRS scores with the outcome disappeared when conditions considered to be 'concordant' with the endpoint were excluded from the calculation of the scores. Importantly, among the 163 no-PAD subjects CIRS scores did not differ between those with and without an event. Conversely, in the 60 PAD patients, the CIRS-IS score calculated excluding the 'concordant' conditions was associated with an increased cardiovascular risk (RR = 4.03, 95% confidence interval (CI) 1.05-15.37, P = 0.042) after adjustment for potential confounders. The corresponding RR for the CIRS-CI was 1.43 (95% CI 1.03-1.98, P = 0.032). Furthermore, both CIRS scores improved the predictive value of ankle/brachial index, which is the most powerful prognostic indicator in PAD.
  
  
  CONCLUSIONS
  Our findings indicate that overall comorbidity, and not only cardiovascular comorbidity, must be considered for prediction of myocardial infarction and stroke in PAD.
authors.affiliation: Department of Clinical Medicine and Cardiovascular and Immunological Sciences, University of Naples 'Federico II', Naples, Italy. brevetti@unina.it
authors.forename: G
authors.initials: G
authors.lastname: Brevetti
authors.forename: G
authors.initials: G
authors.lastname: Giugliano
authors.forename: G
authors.initials: G
authors.lastname: Oliva
authors.forename: S
authors.initials: S
authors.lastname: Lanero
authors.forename: J I
authors.initials: JI
authors.lastname: De Maio
authors.forename: M
authors.initials: M
authors.lastname: Chiariello
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000453:epidemiology; D016491:Peripheral Vascular Diseases / Q000453:epidemiology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology