The Relationship Between Body Mass Index and Long-Term Outcomes Following Traumatic Injury

Abstract

Introduction: Little is known about the relationship between body mass index (BMI), a function of mass and height (mass_kg/height²_m) and long-term outcomes among traumatic injury survivors. In this prospective cohort study, we investigate the relationship between BMI and long-term health outcomes in the trauma population.

Methods: Adult trauma survivors with an injury severity score ≥9 admitted to one of three level 1 trauma centers, from January 1, 2015 to December 31, 2022, were surveyed via telephone between 6 and 12 mo postinjury. Participants were stratified into one of five groups by BMI at the time of trauma: L-BMI (BMI <18.5), N-BMI (BMI 18.5-24.9), H1-BMI (BMI 25-29.9), H2-BMI (BMI 30-34.9), and H3-BMI (BMI ≥35); N-BMI was used as the referent. Mental and physical health-related quality of life scores, pain, new functional limitations, and hospital readmissions were evaluated. Univariate and multivariate analyses were used to compare outcomes between study groups.

Results: 3830 patients were included. Of those, 124 were L-BMI (3.2%), 1495 N-BMI (39%), 1318 H1-BMI (34.4%), 541 H2-BMI (14.1%), and 352 H3-BMI (9.2%). L-BMI was associated with adverse physical (b = -3.13, CI = -5.71 to -0.55, P = 0.017) and mental health (b = -3.17, CI = -5.87 to -0.46, P = 0.022) outcomes 6-12 mo postinjury compared to the referent. H1-BMI and H2-BMI had higher odds of wo`rse physical outcomes (b = -1.47, CI = -2.42 to -0.52, P = 0.002; b = -3.11, CI = - 4.33 to -1.88, P ≤ 0.001, respectively) and chronic pain (adjusted odds ratio (aOR) = 1.24, CI = 1.04-1.47, P = 0.016; aOR = 1.52, CI = 1.21-1.90, P ≤ 0.001, respectively). Patients with H3-BMI had higher odds of worse physical outcomes compared to N-BMI (b = -4.82, CI = -6.28 to -3.37, P ≤ 0.001), chronic pain (aOR = 2.11, CI = 1.61-2.78, P ≤ 0.001), all-cause hospital readmissions (aOR = 1.62, CI = 1.10-2.34, P = 0.013), and new functional limitations (aOR = 1.39, CI = 1.08-1.79, P = 0.01).

Conclusions: BMI variance above or below N-BMI is associated with worse long-term outcomes following traumatic injury.

Keywords: BMI; Functional outcomes; Long-term outcomes; Trauma.