48. Identification of risk factors for readmission risk in patients undergoing ACDF: a predictive risk scale

Abstract

BACKGROUND CONTEXT Anterior cervical discectomy and fusion (ACDF) is the most common surgical treatment for a variety of cervical disk pathologies. With the Center for Medicare and Medicaid Services (CMS) selecting readmissions as a key measure of health care quality, increasing focus has been generated on the topic of reducing readmissions. PURPOSE The objective of this study was to analyze readmission rates in patients across several large state databases, analyze which factors were associated with risk of readmission, and develop a numeric scale for clinicians to utilize for prediction of readmission risk. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A total of 91,550 ACDF surgeries were recorded in the State Inpatient Database (SID) of NY and CA between 2006 and 2014, which made up the derivation cohort to identify risk factors. There were 87,655 ACDF surgeries recorded in the SID from FL and WA over the same time period, making up the validation cohort. OUTCOME MEASURES Readmission status within 30 days and goodness-of-fit of regression curve after application of scale to the validation cohort. METHODS Risk factors for readmission were identified using univariate and multivariate regression analysis of the derivation cohort. After identification of risk factors, odds ratios were then used to generate a predictive scale that was tested utilizing the validation cohort. An exponential regression model was applied to determine the goodness-of-fit of the scale to the readmission risk in the validation cohort. RESULTS Overall readmission rates within 30 days of discharge were 5.68% and 5.29% in the derivation and validation cohorts, respectively. In both cohorts, patients with renal failure and congestive heart failure were readmitted most often. On multivariate analysis of the derivation cohort, age greater than 80 years (OR, 1.74) male gender (OR, 1.16), Medicaid Insurance (OR, 1.99), Medicare Insurance (OR, 1.72), self-pay insurance (OR, 1.42), anemia (OR, 1.45), chronic lung disease (OR, 1.23), coagulopathy (OR, 1.42), depression (OR, 1.15), diabetes (OR, 1.24), fluid and electrolyte disorder (OR, 1.63), hypertension (OR, 1.09), liver disease (OR, 1.34), and renal failure (OR, 1.79) were found to be statistically significant predictors for readmission. These factors were incorporated into a numeric risk scale that, when tested on the validation cohort, could explain 95.5% of the variability in readmission rate. CONCLUSIONS Overall 30-day readmission following ACDF surgery was 5-6%. Factors including advanced age, male gender, Medicaid insurance, Medicare insurance, anemia, lung disease, congestive heart failure, coagulopathy, depression, diabetes, electrolyte disorder, hypertension, liver disease, and renal failure were found to be significant risk factors for 30-day readmission following ACDF surgery. A novel risk scale based on these factors may be helpful in identifying patients who require additional optimization to reduce perioperative morbidity. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.