Association between polypharmacy at the emergency department and long-term mortality in critically ill older patients receiving mechanical ventilation: a single- center retrospective cohort study

Association between polypharmacy at the emergency department and long-term mortality in critically ill older patients receiving mechanical ventilation: a single- center retrospective cohort study

Polypharmacy, Critical illness, Older adults, Mortality, Emergency medical services

Background Polypharmacy is increasingly prevalent among older adults, and is associated with adverse health
outcomes. However, its prognostic impact in emergency care settings remains unclear, particularly in critically ill
older patients requiring mechanical ventilation. Therefore, this study aimed to evaluate the association between
polypharmacy at the emergency department and long-term mortality in critically ill older patients who required
mechanical ventilation.
Methods We conducted a retrospective cohort study of emergency department patients aged≥65 years who
received mechanical ventilation at a Japanese university hospital between April 2015 and December 2024. Patients
were categorized into a polypharmacy group (≥5 regular medications at admission) or a non-polypharmacy group
(fewer medications at admission). Survival was comparatively analyzed using Kaplan–Meier curves and the log-rank
test. Cox proportional hazards regression analysis was performed to examine the association between polypharmacy
at admission (reference: non-polypharmacy) and long-term mortality while adjusting for age, Charlson comorbidity
index, and the Sequential Organ Failure Assessment (SOFA) score modeled as a continuous variable. In addition, we
similarly analyzed the association between polypharmacy status at discharge among patients discharged alive and
long-term mortality.
Results The study cohort comprised 533 patients (non-polypharmacy: 207 patients, polypharmacy: 326 patients).
The median follow-up duration was 2.1 months (interquartile range [IQR], 0.6–11.7 months; maximum, 112.7 months).
Among patients discharged alive, the median follow-up duration was 3.6 months (IQR, 1.0–19.6 months). After
adjustment for age, Charlson comorbidity index, and SOFA score, patients with polypharmacy at admission were not
independently associated with all-cause mortality (hazard ratio [HR]: 1.17, 95% confidence interval [CI]: 0.85–1.60).

Yoshihiro Nakamura1

, Takeshi Umegaki2*, Kota Nishimoto2

, Takashi Muroya1

, Takahiko Kamibayashi2
and

Yasuyuki Kuwagata1

https://doi.org/10.1186/s12873-025-01463-x

2026

PERI IRAWAN

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