Prognostic value of Charlson comorbidity index at 30 days and 1 year after acute myocardial infarction

Introduction and objectives. The Charlson comorbidity index (CCI), an indicator of comorbidity, has been used as an adjusting variable in multivariate models. Because of its prognostic value per se for cardiovascular complications after acute myocardial infarction (AMI), we sought to determine the predictive value of the CCI for all-cause mortality and recurrent AMI 30 days and 1 year after the index event. Patients and method. We analyzed 1035 consecutive patients admitted with the diagnosis of AMI (ST elevation=508 and non-ST elevation=527). The composite end-point was determined after 30 days (13.9%) and 1 year (26.3%) of follow-up. The CCI was calculated on admission, and other variables with prognostic value were also recorded. CCI was stratified in 4 categories: 1: CCI=O (control), 2: CC1=1, 3: CCI=2,4: CCIgreater than or equal to3. Cox proportional risks analysis was used for the multivariate analysis, and the C-statistic was calculated to assess the discriminative power of the models. Results. Hazard ratios (95% Cl) estimated for each category of CCI were: 2=1.69 (1.10-2.59), 3=1.78 (1.08-2.92) and 4=1.57 (0.87-2.83) at 30 days; 2=1.62 (1.18-2.23), 3=2.00 (1.39-2.89) and 4=2.24 (1.50-3.36) at 1 year. Comparisons with the C-statistic between the nested multivariate models (with and without CCI) yielded values of 0.765 vs 0.750 after 30 days, and 0.751 vs 0.735 after 1 year. Conclusions. Our data indicate that CCI is an independent predictor of mortality or recurrent AMI 30 days and 1 year after the index AMI.