Table 3. Instrumental variable regressions comparing IV and oral acetaminophen patients^*.

	Difference	95% Confidence Interval		p-value
Length of Stay (days)	-0.80	-0.92	-0.68	<0.0001
Hospitalization Cost ($)	-2,449.0	-2902.4	-1995.6	<0.0001
Morphine Equivalent Dose (mg)	-1.41	-3.43	0.61	0.17

*Two-stage least squares with quarterly rate of IV acetaminophen use at the hospital as the instrument. Adjusted for patient age, gender, race, APR-DRG Severity of Illness and Risk of Mortality, year of admission, admitting physician type, hospital type (academic), hospital location (urban/rural), and number of beds. Oral Acetaminophen is the reference group.