A disease-specific comorbidity index for predicting mortality in patients admitted to hospital with a cardiac condition.

BACKGROUND: Comorbidity indexes derived from administrative databases are essential tools of research in global health. We sought to develop and validate a novel cardiac-specific comorbidity index, and to compare its accuracy with the generic Charlson-Deyo and Elixhauser comorbidity indexes. METHODS: We derived the cardiac-specific comorbidity index from consecutive patients who were admitted to hospital at a tertiary-care cardiology hospital in Quebec. We used logistic regression analysis and incorporated age, sex and 22 clinically relevant comorbidities to build the index. We compared the cardiac-specific comorbidity index with refitted Charlson-Deyo and Elixhauser comorbidity indexes using the C-statistic and net reclassification improvement to predict in-hospital death, and the Akaike information criterion to predict length of stay. We validated our findings externally in an independent cohort obtained from a provincial registry of coronary disease in Alberta. RESULTS: The novel cardiac-specific comorbidity index outperformed the refitted generic Charlson-Deyo and Elixhauser comorbidity indexes for predicting in-hospital mortality in the derivation population (n = 10 137): C-statistic 0.95 (95% confidence interval [CI] 0.94-0.9) v. 0.81 (95% CI 0.77-0.84) and 0.86 (95% CI 0.82-0.89), respectively. In the validation population (n = 17 877), the cardiac-specific comorbidity index was similarly better: C-statistic 0.92 (95% CI 0.89-0.94) v. 0.76 (95% CI 0.71-0.81) and 0.82 (95% CI 0.78-0.86), respectively, and also numerically outperformed the Charlson-Deyo and Elixhauser comorbidity indexes for predicting 1-year mortality (C-statistic 0.78 [95% CI 0.76-0.80] v. 0.75 [95% CI 0.73-0.77] and 0.77 [95% CI 0.75-0.79], respectively). Similarly, the cardiac-specific comorbidity index showed better fit for the prediction of length of stay. The net reclassification improvement using the cardiac-specific comorbidity index for the prediction of death was 0.290 compared with the Charlson-Deyo comorbidity index and 0.192 compared with the Elixhauser comorbidity index. INTERPRETATION: The cardiac-specific comorbidity index predicted in-hospital and 1-year death and length of stay in cardiovascular populations better than existing generic models. This novel index may be useful for research of cardiology outcomes performed with large administrative databases.

Triple-valve surgery: clinical results of a three-decade experience.

BACKGROUND AND AIM OF THE STUDY: Triple-valve disease is a challenge that surgeons face periodically, yet the clinical benefits of triple-valve surgery, in relation to the high operative risk, are not well known. The study aims were to describe the early and late mortality associated with triple-valve surgery, to assess the risk factors, and describe the long-term outcomes. METHODS: A retrospective analysis of 178 consecutive triple-valve surgeries performed at the Montreal Heart Institute between 1977 and 2008 was performed. The median follow up was 5.0 years (inter-quartile range: 1.6 to 9.4 years). RESULTS: Among 170 patients (122 females, 48 males; mean age 60 +/- 11 years), the preoperative NYHA functional class was > or = III/IV in 93% of cases; 61% of the patients had undergone previous cardiac surgery. The operative mortality was 12% between 1999 and 2008, and 25% between 1977 and 1998 (p = 0.033). Independent risk factors between 1999 and 2008 period included tricuspid regurgitation severity (OR = 13.71; p = 0.03) and the presence of a right intraventricular pacemaker lead (OR = 11.25; p = 0.039). Survival rates at five and 10 years were 61 +/- 4% and 38 +/- 5%, respectively. A lower left ventricular ejection fraction at discharge was associated with a poor late survival, independent of patient age and gender (OR = 0.95; p = 0.035). Twenty-three patients (18%) required reoperation during the follow up period, at which time the NYHA functional class was improved compared to baseline (p < 0.001). CONCLUSION: Although triple-valve surgery is associated with substantial operative mortality, this situation has improved significantly over the years. Currently, survivors experience a significant improvement in their cardiac functional capacity, justifying the continued use of triple-valve procedures, though preferably earlier during the course of the disease.