Abstract: FR-PO0047
Effect of Body Mass Index on Incidence and Outcomes of AKI in Patients in the Intensive Care Unit (ICU)
Session Information
- AKI: Epidemiology, Risk Factors, and Prevention
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 101 AKI: Epidemiology, Risk Factors, and Prevention
Authors
- Wei, Lifang, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Kashani, Mehdi, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Singh, Waryaam, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Suppadungsuk, Supawadee, Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand
- Dong, Yue, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Kashani, Kianoush, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background
Obesity is an established risk factor for chronic kidney disease, but its association with acute kidney injury (AKI) in critically ill patients and related outcomes remains uncertain. Our project is to investigate the relationship between body mass index (BMI), AKI incidence, and clinical outcomes in ICU patients.
Methods
We conducted a retrospective cohort study of 78,139 adult ICU patients admitted to Mayo Clinic (2007–2017). Patients were stratified based on BMI to underweight (BMI<18.5), normal (BMI18.5–24.9), overweight (BMI25–29.9), and obese (BMI≥30). AKI was defined using KDIGO criteria. Multivariable logistic regression and fractional polynomial models assessed associations between BMI and AKI, mortality, and recovery outcomes.
Results
AKI occurred in 28.6% of patients, with incidence progressively increasing with BMI from underweight (19.8%) to obese (31.1%) (p<0.001). Obesity was independently associated with AKI risk (adjusted odds ratio [aOR] 1.62, 95% CI 1.55–1.70), while being underweight was associated with a lower AKI risk (aOR 0.67, 95% CI 0.58–0.76). Despite higher AKI risk, obese patients had lower in-hospital mortality (aOR 0.75) and shorter ICU/hospital stays, while underweight individuals had the highest ICU (5.0%) and in-hospital (10.6%) mortality rates.
Conclusion
Obesity is associated with a higher AKI risk in ICU, while it may confer a survival advantage, supporting the “obesity paradox.” Conversely, underweight patients experience lower AKI incidence but worse outcomes. This paradox could be due to delayed AKI diagnosis due to lower skeletal muscle mass in underweight individuals than in obese patients. BMI should be integrated into ICU risk stratification to guide individualized AKI prevention and management strategies.