Opioid-related adverse drug events in surgical hospitalizations: impact on costs and length of stay.

BACKGROUND: Opioid analgesics remain a mainstay in the treatment of pain associated with surgical procedures. Such use is associated with adverse drug events (ADEs).

OBJECTIVE: To investigate the impact of opioid-related ADEs on total hospital costs and length of stay (LOS) in adult surgical patients.

METHODS: This was a retrospective matched cohort study using data from computerized medical records. ADE cases were prospectively detected using computerized surveillance and verified by pharmacists. Surgical patients treated at LDS Hospital in Salt Lake City from January 1, 1998, to December 31, 2003, were included. The primary outcomes were costs and hospital LOS associated with opioid-related ADEs and the relationship of opioid dose to ADE events.

RESULTS: Patients experiencing opioid-related ADEs had significantly increased median total hospital costs (7.4% increase; 95% CI 3.83 to 10.96; p < 0.001) and increased median LOS (10.3% increase; 95% CI 6.5 to 14.2; p < 0.001) compared with matched non-ADE controls. The increased costs attributable to ADEs, by surgery type, were general surgery ($676.51; 95% CI 351.50 to 1001.50), orthopedics ($861.50; 95% CI 448.20 to 1274.80), and obstetrics/gynecology ($540.90; 95% CI 281.40 to 800.40). Similarly, increased LOS attributable to ADEs, by surgery type, were general surgery (0.64 days; 95% CI 0.40 to 0.88), orthopedics (0.52 days; 95% CI 0.33 to 0.71), and obstetrics/gynecology (0.53 days; 95% CI 0.33 to 0.72). Higher doses of opioids were associated with increased risk of experiencing ADEs (OR 1.3; 95% CI 1.07 to 1.60; p = 0.01).

CONCLUSIONS: Opioid-related ADEs following surgery were associated with significantly increased LOS and hospitalization costs. These ADEs occurred more frequently in patients receiving higher doses of opioids.