Determinants of length of stay in surgical ward after coronary bypass surgery: glycosylated hemoglobin as a predictor in all patients, diabetic or non-diabetic.

BACKGROUND: Reports on the determinants of morbidity in coronary artery bypass graft surgery (CABG) have focused on outcome measures such as length of postoperative stay in the Intensive Care Unit (ICU). We proposed that major comorbidities in the ICU hampered the prognostic effect of other weaker but important preventable risk factors with effect on patients' length of hospitalization. So we aimed at evaluating postoperative length of stay in the ICU and surgical ward separately.

METHODS: We studied isolated CABG candidates who were not dialysis dependent. Preoperative, operative, and postoperative variables as well as all classic risk factors of coronary artery disease were recorded. Using multivariate analysis, we determined the independent predictors of length of stay in the ICU and in the surgical ward.

RESULTS: Independent predictors of extended length of stay in the surgical ward ( > 3 days) were a history of peripheral vascular disease, total administered insulin during a 24-hour period after surgery, glycosylated hemoglobin (HbA1c), last fasting blood sugar of the patients before surgery, and inotropic usage after cardiopulmonary bypass. The area under the Receiver Operating Characteristic Curve (AUC) was found to be 0.71 and Hosmer-Lemeshow (HL) goodness of fit statistic p value was 0.88. Independent predictors of extended length of stay in the ICU ( > 48 hours) were surgeon category, New York Heart Association functional class, intra-aortic balloon pump, postoperative arrhythmias, total administered insulin during a 24-hour period after surgery, and mean base excess of the first 6 postoperative hours (AUC = 0.70, HL p value = 0.94).

CONCLUSION: This study revealed that the indices of glycemic control were the most important predictors of length of stay in the ward after cardiac surgery in all patients, diabetic or non-diabetic. However, because HbA1c level did not change under the influence of perioperative events, it could be deemed a valuable measure in predicting outcome in CABG candidates.