Study design: Retrospective cohort utilizing the National Inpatient Sample (NIS) 2003 to 2014.
Objective: To investigate the association of opioid dependence with prolonged length of stay (LOS), costs, and surgical complications in elective one-to-two level lumbar fusion.
Summary of background data: Opioids are the most commonly prescribed drug class to treat back pain. Few studies have examined the impact of opioid dependence on spinal fusion outcomes. The data available show inconsistent conclusions regarding the association between opioid dependence and LOS.
Methods: Data from 1,826,868 adult elective one-to-two level lumbar fusion discharges in the NIS from 2003 to 2014 were included. Discharges were categorized into an opioid-dependent or unaffected cohort based on the presence or absence of an International Classification of Disease, Ninth Revision-Clinical Modification (ICD-9-CM) code for opioid dependence. Incidence of opioid dependence was compared between 2003 and 2014 via adjusted Wald tests. Patient and surgical characteristics, costs, and complications were compared between cohorts via chi-square tests or adjusted Wald tests for categorical and continuous variables, respectively. Patient and surgical factors were tested for association with prolonged LOS via univariable logistic regressions, and significant (P ≤ 0.01) factors were included in a multivariable logistic regression.
Results: Seven thousand nine hundred sixty-four (0.44%) discharges included a diagnosis of opioid dependence. The incidence of opioid dependence increased from 2003 to 2014. Opioid dependence was associated with an adjusted 2.11 times higher odds of prolonged LOS. Opioid-dependent discharges accrued higher costs and had higher frequencies of infection, device-related complications, hematoma- or seroma-related complications, acute posthemorrhagic anemia, and pulmonary insufficiency.
Conclusion: This nationally-representative study suggests that opioid dependence is associated with prolonged LOS in lumbar fusion, as well as higher costs and higher frequencies of surgical complications. Further investigations are needed to determine the optimal method to treat opioid-dependent patients who require lumbar fusion.
Level of evidence: 3.