Title:
Relationship between potential opioid-related adverse effects and hospital length of stay in patients receiving opioids after orthopedic surgery.

Abstract:
To determine whether there is an association between opioid-related adverse effects and postoperative hospital length of stay (p-LOS).
Retrospective medical record review.
Large academic medical center.
Random sample of 402 patients (mean age 60.2 yrs, 50.3% female) who underwent orthopedic spine, hip, knee, or shoulder surgery during 2007 and received opioids during or after the procedure.
Potential opioid-related adverse effects were identified by using established criteria. Bivariate and multivariate analyses (generalized linear regression model, log transformed) were used to identify predictors of p-LOS. The model also estimated the effect of specific types of adverse effects and adverse-effect combinations on p-LOS. Mean ± SD p-LOS was 3.0 ± 2.1 days; median oral morphine equivalent postoperative dose was 60 mg/day. More than half of the patients (54.2%) experienced one or more adverse effects, 25.6% experienced two or more adverse effects, and 7.2% experienced three or more adverse effects. The composite of nausea and vomiting was experienced by 36.1% of study patients, and 12.6% had at least one emesis episode. Constipation and confusion were documented in 6.5% and 3.7% of patients, respectively. Constipation (p<0.0001), emesis (p<0.001), and confusion (p<0.01) were associated with increased p-LOS after adjusting for other significant variables. Patients with constipation had an adjusted 49% (95% confidence interval [CI] 25-77%) longer p-LOS (additional 1.4 days) compared with patients without constipation. Emesis and confusion significantly increased p-LOS by 25% (95% CI 10-42%) and 38% (95% CI 11-72%), respectively. Incremental increases in p-LOS for patients with two adverse effects (p=0.02), three adverse effects (p<0.001), and four adverse effects (p<0.001) versus patients with no adverse effects were 15%, 40%, and 82%, respectively.
Constipation, emesis, and confusion were associated with increased p-LOS in patients receiving opioids after orthopedic surgery. In addition, there was a significant linear relationship between the number of adverse effects/patient and increased p-LOS, and the strength of the association increased as the number of adverse effects increased. Although the opioid dosages and adverse-effect rates were typical, these findings reinforce the need to balance pain management with risk of events.