QJM Advance Access published online on May 7, 2008
QJM, doi:10.1093/qjmed/hcn056
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The impact of comorbidity burden on the cardiovascular risk in the Peripheral Arteriopathy and Cardiovascular Events study
From the Department of Clinical Medicine and Cardiovascular and Immunological Sciences, University of Naples ‘Federico II’, Naples, Italy
Address correspondence to Gregorio Brevetti, MD, via G. Iannelli 45/A 80131 Napoli, Italy. email: brevetti{at}unina.it
Received 23 May 2007 and in revised form 16 November 2007
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Abstract |
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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.
Aim: 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.
Design: 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.