METHODS: In this retrospective cross-sectional study, patients aged ≥65 years intubated at the ED of University of Malaya Medical Centre, Kuala Lumpur, Malaysia, from 2015 to 2019 were studied. The association between age, gender, place of inhabitation, Identification of Seniors at Risk (ISAR) score for frailty, Charlson Comorbidity Index (CCI), Acute Physiology and Chronic Health Evaluation-II (APACHE-II) score, indication for intubation, and diagnosis on admission with in-hospital mortality (primary outcome) and duration of ventilation, and length of stay (secondary outcomes) were evaluated using univariate analysis and Cox's regression survival analysis.

RESULTS: 889 cases aged 65 years and above were studied (61.5% male). The rate of in-hospital mortality was 71.4%. There was a significant association between age (p < 0.001), nursing home residency (p = 0.008), CCI≥ 5 (p = 0.001), APACHE-II (p < 0.001), pre-intubation Glasgow Coma Scale (GCS) (p < 0.001), cardiac arrest as indication of intubation (p < 0.001), diagnosis on admission (p < 0.001), length of stay (p < 0.001), and length of ventilation (p = 0.003) and in-hospital mortality. Age ≥ 85 years (HR= 1.270; 95%CI=1.074 to 1.502) and 75 to 84 years (HR=1.642; 95%CI=1.167 to 2.076), cardiac arrest as indication of intubation (HR: 1.882; 95% CI: 1.554 - 2.279), and APACHE-II scores 25 - 34 (HR: 1.423; 95% CI: 1.171 - 1.730) and ≥ 35 (HR: 1.789; 95%CI: 1.418 - 2.256) were amongst the independent predictive factors of in-hospital mortality.