Assessing open heart surgery mortality in Catalonia (Spain) through a predictive risk model

• Published in: European journal of cardio-thoracic surgery 1997-03, Vol.11 (3), p.415-423
• Main Authors: PONS, J. M. V, GRANADOS, A, ESPINAS, J. A, BORRAS, J. M, MARTIN, I, MORENO, V
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Cardiac Surgical Procedures - mortality; Cause of Death; Female; Hospital Mortality; Humans; Male; Medical sciences; Middle Aged; Models, Statistical; Risk; Spain - epidemiology; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Survival Analysis
• ISSN: 1010-7940; 1873-734X
• DOI: 10.1016/S1010-7940(96)01061-5

OBJECTIVE: To develop a risk stratification model to assess open heartsurgery mortality in Catalonia (Spain) in order to use risk-adjustedhospital mortality rates as an approach to analyze quality of care.METHODS: Data were prospectively collected through a specific data- sheetduring 6 1/2 months in consecutive adult patients subjected to open heartsurgery. The dependent variable was surgical mortality, and independentvariables included were presurgical (sociodemographic data, clinicalantecedents, morphological and functional studies) and surgical. The modelwas built on a subsample (70% of study population) through univariate andlogistic regression analysis and validated in the rest of the sample.RESULTS: The total sample was of 1309 procedures in seven hospitals; 47% ofthem were valve procedures. The overall crude mortality rate was 10.9% andvaried among centers (range, 2.8-14.8%). Risk factors included in the modelreceived a weight based on the logistic regression coefficient and a scorewas generated for each patient. The factors with the highest weight werepatient older than 80 and second reoperation. Score was stratified in fivecategories of increasing risk. There was a good agreement between observedand predicted mortality rates in the validation group. Overall patientdistribution was as follows: 52% low risk level, 16% fair, 13% high, 12%very high, and 6% extremely high risk level. Mortality rate increased from4.2% in the low risk to 54.4% in the highest risk group. Case mixadjustment was performed through the risk score level. There werestatistically significant differences in the risk profiles of patientsadmitted among centers. After adjustment by risk profiles, there were nodifferences in mortality by hospital. CONCLUSION: A risk stratificationmodel through a multicentric, prospective and exhaustive collection of datain all types of open heart procedures was developed. In spite of widedifferences on crude rates and in the risk profiles of patients admitted,we did not find statistically significant differences in adjusted mortalityrates among centers. Timely and accurate information about surgicaloutcomes can lead to improvements in clinical practice and quality ofcare.