The Downstream Effects of Prehospital Opioid Dosing in Older Adults: A Retrospective Cohort Study.

BACKGROUND

Older adults experience age-related physiological changes that alter the pharmacokinetics and pharmacodynamics of certain medications, which may necessitate reduced dosing. Our objective was to assess emergency department (ED) and hospital outcomes of older patients administered opioids by emergency medical services (EMS) clinicians.

METHODS

Retrospective cohort study of adults ≥ 65 years who received an opioid between 2019 and 2024 within a health system-affiliated EMS agency. We excluded patients with an advanced airway and those with no documented weight. Maximum single and cumulative weight-based opioid dosages were classified as low, therapeutic, or high. Outcomes were measured in the ED/hospital and compared using Poisson regression with Huber/White standard errors, adjusted for age, sex, vitals, Glascow Coma Scale, emergency severity index, and chief concern. Results were reported as adjusted risk ratios (aRRs).

RESULTS

A total of 6406 patients, including 747 (11.7%, 95% CI: 10.9-12.5) with a high opioid dose, 3663 (57.2%, 95% CI: 56.0-58.4) with a therapeutic dose, and 1996 (31.2%, 95% CI: 30.0-32.3) with a low dose, were included. Receipt of a high maximum single opioid dose versus a low/therapeutic dose (excluding patients receiving a concomitant sedative) was associated with increased risk of altered responsiveness (aRR = 1.28, 95% CI: 1.03-1.58) and delirium (aRR = 2.43, 95% CI: 1.08-5.45) in the ED/hospital setting. When 311 (4.9%) patients who received a concomitant sedative were included, patients who received a high opioid dose similarly had an increased risk of altered responsiveness (aRR = 1.28, 95% CI: 1.06-1.56) and delirium (RR = 2.65, 95% CI: 1.25-5.59), compared to a low/therapeutic dose. There was no difference in outcomes of hypoxia, death within 30 days, or ED length of stay between dose groups.

CONCLUSION

Prehospital administration of high opioid doses to older patients was associated with increased rates of altered responsiveness and delirium. These findings highlight how out-of-hospital care can impact a patient's ED and hospital course.