Obese trauma patients have increased need for dialysis

• Published in: European journal of trauma and emergency surgery (Munich : 2007) Vol. 46; no. 6; pp. 1327 - 1334
• Main Authors: Farhat, Ahmed, Grigorian, Areg, Nguyen, Ninh T., Smith, Brian, Williams, Barbara J., Schubl, Sebastian D., Joe, Victor, Elfenbein, Dawn, Nahmias, Jeffry
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2020; Springer Nature B.V
• Subjects: Body mass index; Critical Care Medicine; Emergency medical care; Emergency Medicine; Hemodialysis; Intensive; Medicine; Medicine & Public Health; Mortality; Obesity; Original Article; Sports Medicine; Surgery; Surgical Orthopedics; Trauma; Traumatic Surgery; Obesity; Dialysis; Renal replacement therapy; Trauma; Acute kidney injury
• ISSN: 1863-9933; 1863-9941
• DOI: 10.1007/s00068-019-01147-9

Purpose
Obesity is a risk factor for the development of acute kidney injury but its effect on the need for dialysis in trauma has not been elucidated. Additionally, the contribution that obesity has towards risk of mortality in trauma is unclear. We hypothesized that patients with a higher body mass index (BMI) will have a higher risk for need of dialysis and mortality after trauma.
Methods
This is a retrospective analysis using the National Trauma Data Bank. All patients ≥ 8 years old were grouped based on BMI: normal (18.5–24.99 kg/m
2
), obese (30–34.99 kg/m
2
), severely obese (35–39.99 kg/m
2
) and morbidly obese (≥ 40 kg/m
2
). The primary outcome was hemodialysis initiation. The secondary outcome was mortality during the index hospitalization.
Results
From 988,988 trauma patients, 571,507 (57.8%) had a normal BMI, 233,340 (23.6%) were obese, 94,708 (9.6%) were severely obese, and 89,433 (9.0%) were morbidly obese. The overall rate of hemodialysis was 0.3%. After adjusting for covariates, we found that obese (OR 1.36, CI 1.22–1.52,
p
 < 0.001), severely obese (OR 1.89, CI 1.66–2.15,
p
 < 0.001) and morbidly obese (OR 2.04, CI 1.82–2.29,
p
 < 0.001) patients had a stepwise increased need for hemodialysis after trauma. Obese patients had decreased (OR 0.92, CI 0.88–0.95,
p
 < 0.001), severely obese had similar (OR 1.02, CI 0.97–1.08,
p
 = 0.50) and morbidly obese patients had increased (OR 1.06, CI 1.01–1.12,
p
 = 0.011) risk of mortality after trauma.
Conclusions
Obesity was associated with an increased risk for dialysis after trauma. Mortality risk was reduced in obese, similar in severely obese, and increased in morbidly obese trauma patients suggesting an inflection threshold BMI for risk of mortality in trauma.