ASSESSING OPEN-HEART-SURGERY MORTALITY IN CATALONIA (SPAIN) THROUGH APREDICTIVE RISK MODEL

Objective: To develop a risk stratification model to assess open heart surgery mortality in Catalonia (Spain) in order to use risk-adjusted hospital mortality rates as an approach to analyze quality of care. Me thods: Data were prospectively collected through a specific data-sheet during 6 1/2 months in consecutive adult patients subjected to open h eart surgery. The dependent variable was surgical mortality, and indep endent variables included were presurgical (sociodemographic data, cli nical antecedents, morphological and functional studies) and surgical. The model was built on a subsample (70% of study population) through univariate and logistic regression analysis and validated in the rest of the sample. Results: The total sample was of 1309 procedures in sev en hospitals; 47% of them were valve procedures. The overall crude mor tality rate was 10.9% and varied among centers (range, 2.8-14.8%). Ris k factors included in the model received a weight based on the logisti c regression coefficient and a score was generated for each patient. T he factors with the highest weight were patient older than 80 and seco nd reoperation. Score was stratified in five categories of increasing risk. There was a good agreement between observed and predicted mortal ity rates in the validation group. Overall patient distribution was as follows: 52% low risk level, 16% fair, 13% high, 12% very high, and 6 % extremely high risk level. Mortality rate increased from 4.2% in the low risk to 54.4% in the highest risk group. Case mix adjustment was performed through the risk score level. There were statistically signi ficant differences in the risk profiles of patients admitted among cen ters. After adjustment by risk profiles, there were no differences in mortality by hospital. Conclusion: A risk stratification model through a multicentric, prospective and exhaustive collection of data in all types of open heart procedures was developed. In spite of wide differe nces on crude rates and in the risk profiles of patients admitted, we did not find statistically significant differences in adjusted mortali ty rates among centers. Timely and accurate information about surgical outcomes can lead to improvements in clinical practice and quality of care. (C) 1997 Elsevier Science B.V.