Opioid use disorder before surgery: more postoperative pain and respiratory complications

Design

Systematic review and meta-analysis of 40 studies

Population

Adults with and without opioid use disorder having surgery

Primary outcome

Postoperative pain and composite adverse respiratory events

Effect

Pain OR 2.87 (95% CI 1.63 to 5.06); respiratory events OR 2.10 (1.64 to 2.68); moderate certainty

This systematic review and meta-analysis pooled 40 studies of adults with and without opioid use disorder having surgery. The primary outcomes were postoperative pain and a composite of adverse respiratory events, with readmission, mortality, length of stay and cost as secondary outcomes.

Odds of postoperative pain were higher (OR 2.87, 95% CI 1.63 to 5.06; three studies) and so were odds of composite respiratory events (OR 2.10, 1.64 to 2.68; 19 studies), both with moderate certainty. Pulmonary embolism and pneumonia were more frequent on low to moderate certainty evidence. Readmission at 30 and 90 days, length of stay and total cost were higher on low-certainty evidence, while in-hospital mortality did not clearly differ (very low certainty).

These are associations from observational studies, and the pain estimate rests on only three. The practical message is to identify opioid use disorder before surgery, since it is often unrecorded, and to plan multimodal analgesia and respiratory monitoring.

• Ask about opioid use, including medication for opioid use disorder, at pre-anaesthetic assessment.
• Agree with the addiction team how any maintenance buprenorphine or methadone will be managed around surgery.
• Plan multimodal and regional analgesia early; expect higher pain scores.
• Monitor respiration and oxygenation longer after surgery, and consider the risk of pneumonia and embolism.
• Involve addiction services and the surgical team in discharge planning.

Why it matters

The risk is predictable before the patient reaches theatre, so it can be planned for.

Don't overread it

These are observational associations with low-certainty evidence for several outcomes, and they do not show what intervention would reduce the risk.

The statistics, in plain English

An odds ratio of 2.10 means roughly double the odds of a respiratory event, not double the absolute risk, which depends on baseline risk. The pain result came from only three studies, so its interval of 1.63 to 5.06 is wide. Observational studies cannot separate the disorder from other factors such as smoking or comorbidity.

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