Background: Preoperative severity of illness in patients undergoing coronary artery bypass grafting (CABG) surgery is a major determinant of clinical postoperative outcomes and surgical length of stay (SLOS). Preoperative patient reported health status and social risk have not been quantified as predictors of SLOS post-CABG. Our hypothesis was that poorer self-reported health and greater social risk, as measured by standardized instruments, are significantly associated with extended SLOS defined as greater than or equal to 7 days.
Methods: In the pilot phase of the Washington State Clinical Outcomes Assessment Program (COAP) patients in a case series between 1995 and 1996 at all hospitals with a cardiac surgery program were administered preoperative SF-36 and Seattle Angina Questionnaires (SAQ) in addition to the collection of prospective clinical data with Society of Thoracic Surgeons' compatible definitions (n = 1073). Factors found significant from bivariate analysis were incorporated into a logistic regression model to assess relative association with extended SLOS (>/= 7 days).
Results: The final model included the following elements in descending order of significance: site, SF-36 health perceptions (HP) scale, social risk factors, age, intraaortic balloon pump, congestive heart failure, comorbidity score more than 2, preoperative days more than 2, emergency operation, prior CABG, and gender.
Conclusions: The HP subscore of the SF-36 and the composite social risk factors score were significantly associated with extended SLOS after controlling for other standard clinical variables. "Hospital site" remained the factor with the greatest variance independent of patient severity of illness.