Predictive Model for Length of Stay Among Patients Undergoing Surgery for Grade I Spondylolisthesis: Analysis From the Quality Outcomes Database
Abstract INTRODUCTION Recent changes in healthcare policies implemented as per the Affordable Care Act (ACA) have resulted in providers and hospitals seeking ways to optimize resource utilization and improve patient outcomes. Length of stay (LOS) after surgery has increasingly been used as a surrogate for resource utilization. In the current study, we investigated factors associated with longer LOS after surgery for grade 1 spondylolisthesis. METHODS We queried the Quality Outcomes Database for patients with grade 1 lumbar degenerative spondylolisthesis undergoing a surgical intervention between July 2014 and June 2016. Only those patients enrolled in a multi-side study investigating the impact of fusion on clinical and patient reported outcomes (PROs) among patients with grade 1 spondylolisthesis were evaluated. A multivariable (MV) proportional odds regression model was fitted to determine factors associated with longer LOS. RESULTS A total of 608 patients undergoing surgery were identified (555 single-level, 53 2-level surgeries). Median LOS was 3 d (IQR: 2-4 d). On MV analysis, factors found to be independently predictive of longer LOS included nonroutine home discharge (home with healthcare: OR: 3.5 (1.9-6.8); postacute care: OR: 9.6 (5.2-17.7)), higher baseline ODI (interquartile OR: 1.44 (1.21-1.86)), longer operative time (OR: 1.98 (1.56-2.51), 2-level surgery (OR: 2.91 (1.37-6.21), ref = 1-level surgery); assisted ambulation (OR: 1.9 (1.1-3.3)) and higher American Society of Anesthesiologists (ASA) score (OR: 1.6 (1.1-2.3) while decompression alone (OR: 0.05 (0.03-0.09)), anterior/lateral approaches (OR: 0.25 (0.11-0.56, ref = posterior) and use of MIS (OR: 0.42 (0.30-0.59) were associated with shorter length of stay. Predictor importance analysis revealed that type of surgery (decompression vs fusion), discharge disposition, operative time, use of Minimally invasive spine surgery (MIS) and surgical approach were the top predictors determining duration of stay. CONCLUSION These results from a multi-site study of patients undergoing surgery for grade I spondylolisthesis indicate that patients undergoing fusion, discharged to nonhome, with longer operative time and posterior surgical approaches may have longer LOS. Type of surgery and discharge destination are top predictors determining length of stay.