11
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Does Simplicity Compromise Accuracy in ACS Risk Prediction? A Retrospective Analysis of the TIMI and GRACE Risk Scores

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          The Thrombolysis in Myocardial Infarction (TIMI) risk scores for Unstable Angina/Non-ST–elevation myocardial infarction (UA/NSTEMI) and ST-elevation myocardial infarction (STEMI) and the Global Registry of Acute Coronary Events (GRACE) risk scores for in-hospital and 6-month mortality are established tools for assessing risk in Acute Coronary Syndrome (ACS) patients. The objective of our study was to compare the discriminative abilities of the TIMI and GRACE risk scores in a broad-spectrum, unselected ACS population and to assess the relative contributions of model simplicity and model composition to any observed differences between the two scoring systems.

          Methodology/Principal Findings

          ACS patients admitted to the University of Michigan between 1999 and 2005 were divided into UA/NSTEMI (n = 2753) and STEMI (n = 698) subpopulations. The predictive abilities of the TIMI and GRACE scores for in-hospital and 6-month mortality were assessed by calibration and discrimination. There were 137 in-hospital deaths (4%), and among the survivors, 234 (7.4%) died by 6 months post-discharge. In the UA/NSTEMI population, the GRACE risk scores demonstrated better discrimination than the TIMI UA/NSTEMI score for in-hospital (C = 0.85, 95% CI: 0.81–0.89, versus 0.54, 95% CI: 0.48–0.60; p<0.01) and 6-month (C = 0.79, 95% CI: 0.76–0.83, versus 0.56, 95% CI: 0.52–0.60; p<0.01) mortality. Among STEMI patients, the GRACE and TIMI STEMI scores demonstrated comparably excellent discrimination for in-hospital (C = 0.84, 95% CI: 0.78–0.90 versus 0.83, 95% CI: 0.78–0.89; p = 0.83) and 6-month (C = 0.72, 95% CI: 0.63–0.81, versus 0.71, 95% CI: 0.64–0.79; p = 0.79) mortality. An analysis of refitted multivariate models demonstrated a marked improvement in the discriminative power of the TIMI UA/NSTEMI model with the incorporation of heart failure and hemodynamic variables. Study limitations included unaccounted for confounders inherent to observational, single institution studies with moderate sample sizes.

          Conclusions/Significance

          The GRACE scores provided superior discrimination as compared with the TIMI UA/NSTEMI score in predicting in-hospital and 6-month mortality in UA/NSTEMI patients, although the GRACE and TIMI STEMI scores performed equally well in STEMI patients. The observed discriminative deficit of the TIMI UA/NSTEMI score likely results from the omission of key risk factors rather than from the relative simplicity of the scoring system.

          Related collections

          Most cited references17

          • Record: found
          • Abstract: found
          • Article: not found

          Predictors of hospital mortality in the global registry of acute coronary events.

          Management of acute coronary syndromes (ACS) should be guided by an estimate of patient risk. To develop a simple model to assess the risk for in-hospital mortality for the entire spectrum of ACS treated in general clinical practice. A multivariable logistic regression model was developed using 11 389 patients (including 509 in-hospital deaths) with ACS with and without ST-segment elevation enrolled in the Global Registry of Acute Coronary Events (GRACE) from April 1, 1999, through March 31, 2001. Validation data sets included a subsequent cohort of 3972 patients enrolled in GRACE and 12 142 in the Global Use of Strategies to Open Occluded Coronary Arteries IIb (GUSTO-IIb) trial. The following 8 independent risk factors accounted for 89.9% of the prognostic information: age (odds ratio [OR], 1.7 per 10 years), Killip class (OR, 2.0 per class), systolic blood pressure (OR, 1.4 per 20-mm Hg decrease), ST-segment deviation (OR, 2.4), cardiac arrest during presentation (OR, 4.3), serum creatinine level (OR, 1.2 per 1-mg/dL [88.4- micro mol/L] increase), positive initial cardiac enzyme findings (OR, 1.6), and heart rate (OR, 1.3 per 30-beat/min increase). The discrimination ability of the simplified model was excellent with c statistics of 0.83 in the derived database, 0.84 in the confirmation GRACE data set, and 0.79 in the GUSTO-IIb database. Across the entire spectrum of ACS and in general clinical practice, this model provides excellent ability to assess the risk for death and can be used as a simple nomogram to estimate risk in individual patients.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            A validated prediction model for all forms of acute coronary syndrome: estimating the risk of 6-month postdischarge death in an international registry.

            Accurate estimation of risk for untoward outcomes after patients have been hospitalized for an acute coronary syndrome (ACS) may help clinicians guide the type and intensity of therapy. To develop a simple decision tool for bedside risk estimation of 6-month mortality in patients surviving admission for an ACS. A multinational registry, involving 94 hospitals in 14 countries, that used data from the Global Registry of Acute Coronary Events (GRACE) to develop and validate a multivariable stepwise regression model for death during 6 months postdischarge. From 17,142 patients presenting with an ACS from April 1, 1999, to March 31, 2002, and discharged alive, 15,007 (87.5%) had complete 6-month follow-up and represented the development cohort for a model that was subsequently tested on a validation cohort of 7638 patients admitted from April 1, 2002, to December 31, 2003. All-cause mortality during 6 months postdischarge after admission for an ACS. The 6-month mortality rates were similar in the development (n = 717; 4.8%) and validation cohorts (n = 331; 4.7%). The risk-prediction tool for all forms of ACS identified 9 variables predictive of 6-month mortality: older age, history of myocardial infarction, history of heart failure, increased pulse rate at presentation, lower systolic blood pressure at presentation, elevated initial serum creatinine level, elevated initial serum cardiac biomarker levels, ST-segment depression on presenting electrocardiogram, and not having a percutaneous coronary intervention performed in hospital. The c statistics for the development and validation cohorts were 0.81 and 0.75, respectively. The GRACE 6-month postdischarge prediction model is a simple, robust tool for predicting mortality in patients with ACS. Clinicians may find it simple to use and applicable to clinical practice.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              The Framingham predictive instrument in chronic kidney disease.

              We sought to determine the utility of the Framingham equations in individuals with chronic kidney disease (CKD). The Framingham equations predict incident coronary disease. The utility of these equations is unknown in CKD. We pooled individuals without pre-existing coronary disease age 45 to 74 years from the ARIC (Atherosclerosis Risk In Communities) and CHS (Cardiovascular Health Study) trials with CKD, defined by an estimated glomerular filtration rate of 15 to 60 ml/min/1.73 m(2). Using gender-specific models, we determined 5- and 10-year risk of incident myocardial infarction and fatal coronary disease, and evaluated discriminative and calibration ability of the Framingham equations for predicting coronary events. There were 577 women and 357 men with CKD. Thirty-five men (9.8%) and 30 women (5.2%) and 74 men (20.7%) and 56 women (9.7%) had cardiac events within 5 and 10 years, respectively; 5-year events were predicted in 6.0% and 1.9% and 10-year events in 13.9% and 4.8% of men and women, respectively. For 5-year events, C-statistics assessing discrimination were 0.62 and 0.77, while 10-year C-statistics were 0.60 and 0.73 for men and women, respectively. Calibration was also poor, with Framingham scores generally underpredicting events in individuals with CKD at 5 and 10 years. Discrimination was significantly improved by refitting models with population-specific coefficients, while recalibration improved prediction in women. The Framingham instrument demonstrates poor overall accuracy in predicting cardiac events in individuals with CKD, although refit models can substantially improve discrimination. Calibration in women can be moderately improved with adjustment for higher event rates. Development of CKD-specific equations is needed.
                Bookmark

                Author and article information

                Contributors
                Role: Editor
                Journal
                PLoS One
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, USA )
                1932-6203
                2009
                23 November 2009
                : 4
                : 11
                : e7947
                Affiliations
                [1 ]Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
                [2 ]Cardiovascular Research, Division of Medical and Radiological Sciences, The University of Edinburgh, Edinburgh, Scotland
                [3 ]Canadian Heart Research Centre and Terrence Donnelly Heart Centre, Division of Cardiology, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
                Lerner Research Institute, Cleveland Clinic, United States of America
                Author notes

                Conceived and designed the experiments: HSG. Analyzed the data: KGA UUT EKR JL HSG. Contributed reagents/materials/analysis tools: KGA UUT EKR JL KAAF SGG KAE HSG. Wrote the paper: KGA.

                Article
                09-PONE-RA-12792R1
                10.1371/journal.pone.0007947
                2776353
                19956773
                a74ade48-3d86-4a65-9a66-b7046162b2da
                Aragam et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
                History
                : 8 September 2009
                : 27 October 2009
                Page count
                Pages: 9
                Categories
                Research Article
                Cardiovascular Disorders
                Cardiovascular Disorders/Coronary Artery Disease
                Cardiovascular Disorders/Myocardial Infarction

                Uncategorized
                Uncategorized

                Comments

                Comment on this article