Authors: Hinton J et al.
Source: Anaesthesia Critical Care & Pain Medicine. 2025. Article 101634. DOI: 10.1016/j.accpm.2025.101634
Summary:
In this large bi-national retrospective cohort study, Hinton and colleagues examined the association between body mass index (BMI) and short-term outcomes in the very old critically ill population—specifically nonagenarians and centenarians admitted to the ICU. Despite extensive literature on the so-called “obesity paradox” in critical illness, data in patients aged 90 years and older have been limited.
The investigators analyzed 12,510 ICU admissions over a 15-year period, categorizing patients by admission BMI into underweight, normal weight, overweight, and obese groups. The primary outcome was in-hospital mortality, with secondary analyses examining requirements for organ support. To minimize confounding, entropy-weighted adjustment was used to balance baseline characteristics across BMI groups.
After adjustment, increasing BMI was independently associated with lower in-hospital mortality. Underweight patients had a significantly higher mortality risk compared with normal-weight patients, while obese patients demonstrated a statistically significant survival advantage. Overweight patients had mortality rates similar to the normal-weight group. Importantly, BMI was not associated with differences in the need for vasopressors/inotropes, invasive mechanical ventilation, or renal replacement therapy, suggesting that the observed mortality differences were not simply driven by differential use of life-sustaining treatments.
These findings support the presence of an obesity paradox even in extremely elderly ICU patients, raising questions about the role of nutritional reserves, frailty, sarcopenia, and metabolic resilience in determining outcomes in advanced age. The authors emphasize that BMI alone should not be interpreted as a marker of illness severity or futility in this population, and that individualized assessment remains essential.
What You Should Know:
• Higher BMI was associated with lower in-hospital mortality in ICU patients aged 90 years and older.
• Underweight status conferred the highest mortality risk among BMI categories.
• BMI was not associated with the need for mechanical ventilation, vasopressors, or renal replacement therapy.
• These findings highlight the limitations of using BMI as a simplistic prognostic marker in very old, critically ill patients.
Key Points:
• This study included over 12,000 nonagenarian and centenarian ICU admissions.
• An obesity-associated survival benefit persisted after rigorous entropy-weighted adjustment.
• The results align with the “obesity paradox” observed in younger critical care populations.
• Individualized risk assessment is crucial when caring for the very elderly in the ICU.
Thank you to Anaesthesia Critical Care & Pain Medicine for publishing this important contribution to our understanding of risk stratification and outcomes in the fastest-growing segment of the ICU population.