Authors: Hinton J et al.
Anaesthesia Critical Care & Pain Medicine, 2025 DOI: 10.1016/j.accpm.2025.101634
Summary
This bi-national retrospective cohort study analyzed 12,510 nonagenarians and centenarians admitted to intensive care units over a 15-year period to assess how body mass index (BMI) influences short-term outcomes. Patients were divided into four BMI groups: underweight, normal weight, overweight, and obese. The primary outcome was in-hospital mortality.
The median BMI in the cohort was 24.4 kg/m², with the largest proportion in the normal-weight category. After entropy weighting, an inverse relationship between BMI and mortality emerged: higher BMI was associated with lower in-hospital mortality. Underweight patients had the highest mortality risk, while obese patients had the lowest. Specifically, underweight patients had an 18% increased mortality risk compared with normal-weight patients, while obesity was associated with a 24% reduction in mortality risk. Overweight patients showed no significant difference compared with normal-weight patients.
Importantly, BMI was not associated with the need for inotropes, mechanical ventilation, or renal replacement therapy. Thus, the mortality benefit seen in higher BMI categories was not linked to differences in acute organ support requirements.
These findings support the concept of an “obesity paradox” even in the oldest critically ill patients, suggesting that higher BMI may provide metabolic or physiologic reserve that improves survival in extreme age groups.
What You Should Know
• Study included 12,510 ICU patients aged 90–100+ years.
• Higher BMI was associated with lower in-hospital mortality.
• Underweight patients had the highest mortality risk.
• Obesity reduced mortality by about 24% relative to normal weight.
• BMI did not influence the need for inotropes, ventilation, or dialysis.
• Findings reinforce individualized risk prediction for the very elderly in critical care.
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