Computed tomographic bone mineral density is independently associated with adverse in-hospital outcomes in Dutch level-1 trauma patients.

BACKGROUND: Aging, inactivity, and malnutrition are risk factors for adverse in-hospital outcomes and can manifest in bone loss. Use of bone mineral density (BMD) as an objective marker might improve early identification of patients at risk for complications. AIM: To assess the association of computed tomography (CT) determined BMD values of the first lumbar vertebra with in-hospital complications and outcomes in trauma patients. METHODS: All consecutive hospitalized trauma patients (≥ 16 years) that underwent CT-imaging within 7 days of admission in 2017 were included. Patients with an active infection or antibiotic treatment upon admission, severe neurologic trauma, or an unassessable vertebra were excluded. BMD at the first lumbar vertebra was determined with CT by placing a circular region of interest in homogeneous trabecular bone to obtain mean Hounsfield Units (HU). Regression analyses were performed to assess the association of BMD with in-hospital complications and outcomes. RESULTS: In total, 410 patients were included (median age: 49 years [interquartile range 30-64], 68.3% men, mean BMD 159 ± 66 HU). A total of 94 complications, primarily infection-related, were registered in 74 patients. After adjustment for covariates, a decrease of BMD by one standard deviation was significantly associated with increased risk of complications (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.1-3.1), pneumonia (OR 2.2, 95% CI 1.2-4.5), delirium (OR 4.5, 95% CI 1.7-13.5), and intensive care unit (ICU) admission (OR 1.8, 95% CI 1.1-2.9). CONCLUSION: Bone mineral density of the first lumbar vertebra is independently associated with in-hospital complications, pneumonia, delirium, and ICU admission. These findings could help identify patients at risk early.

Computed Tomography-Based L1 Bone Mineral Density in 624 Dutch Trauma Patients-Are North American Reference Values Valid in Europe?

Opportunistic screening for bone mineral density (BMD) of the first lumbar vertebra (L1) using computed tomography (CT) is increasingly used to identify patients at risk for osteoporosis. An extensive study in the United States has reported sex-specific normative values of CT-based BMD across all ages. The current study aims to validate North American reference values of CT-based bone mineral density in a Dutch population of level-1 trauma patients. All trauma patients aged 16 or older, admitted to our level-1 trauma center during 2017, who underwent a CT scan of the chest or abdomen at 120 kVp within 7 days of hospital admission, were retrospectively included. BMD measurements in Hounsfield Units (HU) were performed manually in L1 or an adjacent vertebra. Student's t-tests were performed to compare the Dutch mean BMD value per age group to the North American reference values. Linear regression analysis and Pearson's correlation coefficient (ρ) calculations were performed to assess the correlation between BMD and age. In total, 624 patients were included (68.4% men, aged 16-95). Mean BMD decreased linearly with 2.4 HU per year of age (ρ = -0.77). Sex-specific analysis showed that BMD of premenopausal women was higher than BMD of men at these ages. Dutch mean BMD values in the age groups over 35 years were significantly lower than the North American reference values. Our findings indicate that using North American BMD thresholds in Dutch clinical practice would result in overdiagnosis of osteoporosis and osteopenia. Dutch guidelines may benefit from population-specific thresholds.