BMI extremes predict distinct trajectories following hip fracture

Area of Science:

• Geriatric Medicine
• Orthopedic Surgery
• Public Health

Background:

• Body Mass Index (BMI) extremes are linked to surgical risks.
• Distinct impacts of underweight and obesity on hip fracture outcomes are not well-defined.
• Elderly patients with hip fractures present varied risks based on BMI.

Purpose of the Study:

• Compare short- and long-term outcomes in elderly hip fracture patients across BMI extremes.
• Investigate the influence of severe underweight and obesity on post-hip fracture complications, mortality, and functional recovery.
• Identify differential risks associated with underweight versus obese status post-hip fracture.

Main Methods:

• Retrospective cohort study using a prospectively collected hip fracture database (2014-2024).
• Comparison of severely underweight (BMI ≤16.5) and class 2+ obese (BMI ≥35) patients against normal-weight controls (BMI 18.5-25.0).
• Analysis of outcomes including complications, intensive care unit (ICU) admission, discharge disposition, mortality, and functional recovery.

Main Results:

• Obese patients had significantly higher odds of ICU admission (OR 5.75) and were less likely to be discharged home (OR 0.31).
• Severely underweight patients faced significantly increased six-month mortality (OR 4.95) compared to normal-weight individuals.
• No significant differences in healing or functional recovery were observed across the BMI groups.

Conclusions:

• Short- and long-term risks following hip fracture diverge based on BMI extremes.
• Obesity is associated with increased short-term morbidity (ICU admission) but not long-term mortality.
• Severe underweight status presents a higher risk of mortality at six months post-hip fracture, despite minimal short-term morbidity.
• Tailored perioperative strategies considering metabolic status are crucial for managing hip fracture patients at BMI extremes.