Identification of variables needed to risk adjust outcomes of coronary interventions: evidence-based guidelines for efficient data collection.
OBJECTIVE
Our objectives were to identify and define a minimum set of variables for interventional cardiology that carried the most statistical weight for predicting adverse outcomes. Though "gaming" cannot be completely avoided, variables were to be as objective as possible and reproducible and had to be predictive of outcome in current databases.


BACKGROUND
Outcomes of percutaneous coronary interventions depend on patient risk characteristics and disease severity and acuity. Comparing results of interventions has been difficult because definitions of similar variables differ in databases, and variables are not uniformly tracked. Identifying the best predictor variables and standardizing their definitions are a first step in developing a universal stratification instrument.


METHODS
A list of empirically derived variables was first tested in eight cardiac databases (158,273 cases). Three end points (in-hospital death, in-hospital coronary artery bypass graft surgery, Q wave myocardial infarction) were chosen for analysis. Univariate and multivariate regression models were used to quantify the predictive value of the variable in each database. The variables were then defined by consensus by a panel of experts.


RESULTS
In all databases patient demographics were similar, but disease severity varied greatly. The most powerful predictors of adverse outcome were measures of hemodynamic instability, disease severity, demographics and comorbid conditions in both univariate and multivariate analyses.


CONCLUSIONS
Our analysis identified 29 variables that have the strongest statistical association with adverse outcomes after coronary interventions. These variables were also objectively defined. Incorporation of these variables into every cardiac dataset will provide uniform standards for data collected. Comparisons of outcomes among physicians, institutions and databases will therefore be more meaningful.
Heart Institute, Providence St. Vincent Medical Center, Portland, Oregon 97225, USA. petervblockvmd@phsor.org
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Block
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Peterson
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Krone
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Kesler
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Hannan
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O'Connor
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Detre
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Peterson
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000706:statistics & numerical data*; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D003327:Coronary Disease / Q000401:mortality* / Q000628:therapy; D003625:Data Collection / Q000706:statistics & numerical data*; D016208:Databases, Factual; D019317:Evidence-Based Medicine; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000628:therapy; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D017410:Practice Guidelines as Topic; D011379:Prognosis; D014481:United States / Q000453:epidemiology