Opioid Escalation in the ICU and 90-Day Readmission After Major Surgery: A Retrospective Cohort Study Using the MIMIC-IV Database

Abstract

Background

Opioid stewardship is central to postoperative critical care, yet the prognostic value of short-term opioid dose escalation in the intensive care unit (ICU) remains unclear. In non-ICU settings, escalating opioid requirements have been associated with poorly controlled pain, postoperative complications, and increased readmission rates. Whether similar relationships exist in critically ill postoperative patients has not been established.

Objective

To determine whether early postoperative opioid escalation during the first 72 hours after major surgery is associated with 90-day hospital readmission among ICU patients.

Methods

This retrospective cohort study used the publicly available Medical Information Mart for Intensive Care IV (MIMIC-IV, version 3.1) database (2008-2022). Adults aged ≥ 18 years admitted to the ICU after major orthopedic, general, or neurosurgical procedures were included. Opioid escalation was defined as total morphine milligram equivalents (MME) administered during hours 48-71 exceeding twice the MME during hours 0-23 after ICU admission. The primary outcome was all-cause hospital readmission within 90 days of discharge. Multivariable logistic regression estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs), controlling for age, sex, Charlson Comorbidity Index (CCI), and surgical category.

Results

Of 613 patients analyzed, mean (SD) age was 65 (15) years and 342 (55.8%) were male. Opioid escalation occurred in 126 patients (20.6%), and readmission in 229 (37.4%). In multivariable logistic regression adjusted for age, sex, Charlson Comorbidity Index, and surgical category, escalation was not associated with readmission (adjusted odds ratio, 1.05; 95% CI, 0.68 to 1.63; P = .83).

Conclusions

In critically ill postoperative patients, short-term opioid escalation was not associated with 90-day readmission. These null findings suggest escalation may be a poor-quality metric in the intensive care unit due to high baseline opioid exposure and continuous monitoring. Further evaluation in non-intensive care unit settings is warranted.