Medicaid payer status and other factors associated with hospital length of stay in patients undergoing primary lumbar spine surgery

Abstract

Objective: The Medicaid patient population and health care costs for spine surgeries among these patients have increased since 2010. Hospital length of stay (LOS) contributes appreciably to hospital costs for patients undergoing primary lumbar spine surgery (PLSS). The aim of this study was to identify independent risk factors for increased LOS in patients undergoing PLSS.

Patients and methods: In a single-center retrospective study, we reviewed demographic and clinical data from electronic medical records for 181 consecutive adult patients who underwent PLSS involving 1-3 levels from July 2014 to July 2017. We performed regression analyses to identify independent risk factors for increased LOS and to quantify their effects as percent changes in LOS.

Results: Among 181 patients who underwent PLSS, the mean LOS was 3.57 days. Based on the Charlson Comorbidity Index (CCI) and American Society of Anesthesiologist (ASA) classification, patients with Medicaid insurance were healthier than non-Medicaid patients (mean CCI: 0.34 versus 0.65; p = 0.041, ASA: 1.71 versus 1.91; p = 0.046) yet Medicaid patients had a longer LOS compared with non-Medicaid patients (mean LOS: 4.03 versus 3.30 days; p = 0.047). There was no significant difference in discharge disposition between Medicaid and non-Medicaid patients (Home = 82.35 % versus 79.65 %; p = 0.855). Medicaid patients also had significantly less spinal levels involved in their surgery (1.44 versus 1.67; p = 0.027). Multivariable regression modeling identified independent risk factors positively associated with increased LOS as age (+1.0 % per year; p = 0.007), Medicaid insurance status (+28.7 %; p = 0.007), and CCI (10.1 % per increment in CCI; p = 0.030). Fusion surgery also was an independent risk factor for increased LOS when compared with laminectomy (-54.1 %; p < 0.001) or discectomy (-51.3 %; p < 0.001).

Conclusions: Increasing age, Medicaid insurance status, higher CCI, and fusion surgery were independently associated with increased LOS after PLSS. This information is useful for preoperative patient counseling, shared decision-making, and risk stratification and may help to further ongoing discussion regarding contributors to rising health care costs. Findings of increased LOS among Medicaid patients will help direct efforts to identify factors that contribute to this health care expense.

Keywords: Charlson Comorbidity Index; Hospitalization; Insurance; Length of stay; Lumbar degenerative disease; Medicaid; Spinal fusion; Spine surgery.