Derivation and validation of a simple inflammation-based risk score system for predicting in-hospital mortality in acute coronary syndrome patients.

BACKGROUND: Accurate assessment of inflammatory status of patients during acute coronary syndrome (ACS) has become of great importance in their risk classification and in the research of new anti-inflammatory therapies.

METHOD: The study cohort included 7396 patients with ACS. We sought to derive and internally validate an inflammation-based score that included high-sensitivity C-reactive protein, white blood cell count, and serum albumin level at admission to evaluate the predictive role of systemic inflammation in the clinical outcome of these patients. We randomly assigned patients into derivation (66.6%) and validation (33.4%) cohorts. A total of four categories of systemic inflammation were defined.

RESULTS: Assessed individually, the three biomarkers were associated with a higher rate of in-hospital mortality. When we combined them into an inflammation score, in-hospital mortality was significantly different across the four categories of inflammation in the derivation cohort (1.8%, 2.8%, 4.1%, and 13.8% for without, mild, moderate, and severe inflammation, respectively; p<0.0001, C-statistic, 0.71). These results were similar in the validation cohort (1.1%, 2.9%, 5.2%, and 12.6%, respectively; p<0.0001, C-statistic, 0.71). After multivariate adjustment, only the category of severe systemic inflammation was associated with a threefold increased risk of in-hospital mortality (odds ratios 3.02, p<0.0001) and was the most powerful predictor of mortality. In the whole cohort, after subsetting patients based on GRACE risk score, the severe inflammation category was associated with a significant increase of in-hospital mortality across all sub-groups, mainly in patients with higher GRACE risk score. The inflammation-based risk score reclassified 25.3% of the population. The net reclassification index was 8.2% (p=0.001).

CONCLUSION: A risk score system based on biomarkers of inflammation readily available at admission in patients with ACS, could better assess the inflammatory status and predict in-hospital mortality, as well as severe systemic inflammation that contributes to a worse outcome independently of clinical risk factors.