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Published on: May 10, 2013
Estimating glomerular filtration rate in acute coronary syndromes: Different equations, different mortality risk
Inês Almeida1, Francisca Caetano2, Sérgio Barra3
1Cardiology Department, Coimbra University Hospital Centre, Portugal inesalm@gmail.com.
Insights
The CKD-EPIcyst equation, using cystatin C, best predicts mid-term mortality in acute coronary syndrome patients. It outperforms the MDRD-4 formula and enhances the GRACE score for improved risk assessment.
Area of Science:
- Cardiology
- Nephrology
- Clinical Epidemiology
Background:
- Renal dysfunction is a key predictor of adverse outcomes in acute coronary syndrome (ACS) patients.
- New estimated glomerular filtration rate (eGFR) equations (CKD-EPIcreat, CKD-EPIcyst, CKD-EPIcreat/cyst) are recommended for assessing renal function.
- The predictive value of these new equations for mortality in ACS patients requires thorough investigation.
Purpose of the Study:
- To evaluate the mid-term mortality predictive value of three new eGFR estimating equations.
- To compare the performance of CKD-EPIcreat, CKD-EPIcyst, and CKD-EPIcreat/cyst with the traditional MDRD-4 formula.
- To assess the added prognostic power of these equations to existing risk scores.
Main Methods:
- 801 patients hospitalized for ACS were included and followed for approximately 24 months.
- Patients were stratified into high-risk (eGFR<60ml/min/1.73m²) and low-risk (eGFR≥60ml/min/1.73m²) groups based on each eGFR equation.
- Predictive performance was compared using receiver operating characteristic curves (AUCs) and net reclassification improvement (NRI).
Main Results:
- The CKD-EPIcyst equation demonstrated the highest discrimination for mid-term mortality (AUC 0.782±0.20), outperforming all other equations.
- CKD-EPIcyst significantly improved risk reclassification compared to the MDRD-4 formula (NRI 11.9%, p=0.003).
- The CKD-EPIcyst equation significantly enhanced the predictive capability of the GRACE score for mid-term mortality.
Conclusions:
- The CKD-EPIcyst equation offers a superior method for assessing mid-term mortality risk in ACS patients.
- Cystatin C-based eGFR estimation provides significant added value for risk stratification in this population.
- These findings support the routine use of CKD-EPIcyst for improved patient management and risk prediction in ACS.
Aims:
Renal dysfunction is a powerful predictor of adverse outcomes in patients hospitalized for acute coronary syndrome. Three new glomerular filtration rate (GFR) estimating equations recently emerged, based on serum creatinine (CKD-EPIcreat), serum cystatin C (CKD-EPIcyst) or a combination of both (CKD-EPIcreat/cyst), and they are currently recommended to confirm the presence of renal dysfunction. Our aim was to analyse the predictive value of these new estimated GFR (eGFR) equations regarding mid-term mortality in patients with acute coronary syndrome, and compare them with the traditional Modification of Diet in Renal Disease (MDRD-4) formula.
Methods And Results:
801 patients admitted for acute coronary syndrome (age 67.3±13.3 years, 68.5% male) and followed for 23.6±9.8 months were included. For each equation, patient risk stratification was performed based on eGFR values: high-risk group (eGFR<60ml/min per 1.73m(2)) and low-risk group (eGFR⩾60ml/min per 1.73m(2)). The predictive performances of these equations were compared using area under each receiver operating characteristic curves (AUCs). Overall risk stratification improvement was assessed by the net reclassification improvement index. The incidence of the primary endpoint was 18.1%. The CKD-EPIcyst equation had the highest overall discriminate performance regarding mid-term mortality (AUC 0.782±0.20) and outperformed all other equations (ρ<0.001 in all comparisons). When compared with the MDRD-4 formula, the CKD-EPIcyst equation accurately reclassified a significant percentage of patients into more appropriate risk categories (net reclassification improvement index of 11.9% (p=0.003)). The CKD-EPIcyst equation added prognostic power to the Global Registry of Acute Coronary Events (GRACE) score in the prediction of mid-term mortality.
Conclusion:
The CKD-EPIcyst equation provides a novel and improved method for assessing the mid-term mortality risk in patients admitted for acute coronary syndrome, outperforming the most widely used formula (MDRD-4), and improving the predictive value of the GRACE score. These results reinforce the added value of cystatin C as a risk marker in these patients.
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