Comparative analysis of length of stay, hospitalization costs, opioid use, and discharge status among spine surgery patients with postoperative pain management including intravenous versus oral acetaminophen.

BACKGROUND: Recovery from spine surgery is oriented toward restoring functional health outcomes while reducing resource use. Optimal pain management is a key to reaching these objectives. We compared outcomes of spine surgery patients who received standard pain management including intravenous (IV) acetaminophen (APAP) vs. oral APAP. METHODS: We performed a retrospective analysis of the Premier database (January 2012 to September 2015) comparing spine surgery patients who received pain management with IV APAP to those who received oral APAP, with no exclusions based on additional pain management. We performed multivariable logistic regression for the discharge and all cause 30-day readmission to the same hospital outcomes and instrumental variable regressions using the quarterly rate of IV APAP use for all hospitalizations by hospital as the instrument in two-stage least squares regressions for length of stay (LOS), hospitalization costs, and average daily morphine equivalent dose (MED) outcomes. Models adjusted for age, gender, race, admission type, 3M All Patient Refined Diagnosis Related Group severity of illness and risk of mortality, hospital size, and indicators for whether the hospital was an academic center and whether it was urban or rural. RESULTS: We identified 112,586 spine surgery patients with 51,835 (46%) having received IV APAP. Subjects averaged 57 and 59 years of age respectively in the IV APAP and oral APAP cohorts and were predominantly non-Hispanic Caucasians and female. In our adjusted models, IV APAP was associated with 0.68 days shorter LOS (95% CI: -0.76 to -0.59, p < .0001), $1175 lower hospitalization costs (95% CI: -$1611 to -$739, p < .0001), 13 mg lower average daily MED (95% CI: -14 mg to -12 mg, p < .0001), 34% lower risk of discharge to a skilled nursing facility (95% CI: 0.63 to 0.69, p < .0001), and 13% less risk of 30-day readmission (95% CI: 0.73 to 1.03). CONCLUSIONS: Compared to oral APAP, managing post-spine-surgery pain with IV APAP is associated with less resource use, lower costs, lower doses of opioids, and improved discharge status.