To identify the risk factors of bone loss in elderly patients with critical illness.

Elderly patients with critical illness admitted to Affiliated Jinhua Hospital, Zhejiang University School of Medicine during July 2020 and July 2021 were enrolled in the study. Quantitative ultrasonography was used to assess the bone mass. Those T value decreases by more than 10% were defined as bone loss. The differences of clinical data between bone loss group and control group were observed by T test, rank sum test, χ² test, and the related risk factors of bone loss were determined by multivariate logistic regression analysis.

A total of 71 elderly patients with critical illness were enrolled in the study, in which 41 patiens were in bone loss group and 30 patients in control group. When compared with control group, patients in bone loss group were more likely to have lower FiO₂, higher sequential organ failure assessment (SOFA) score on ICU admission and more continuous renal replacement therapy (CRRT) treatment, longer mechanical ventilation time, longer braking time (t=-3.516, χ²=8.019, Z=-3.990, -3.161, -2.056, P < 0.05 or < 0.01). Only white blood cell count, C-reactive protein and interleukin-6 on ICU admission showed statistically significant differences between the two groups (t=2.682, Z=-3.108, 3.307, P < 0.01). Multivariate analysis showed that risk factors with bone loss were high SOFA score, high interleukin-6 levels on ICU admission, CRRT treatment and long mechanical ventilation time during ICU stay (OR=1.223, 1.080, 6.635, 1.004, P < 0.05).

Elderly patients with critical illness in ICU have high risk of bone loss. Patients with high SOFA score and IL-6 level on admission, CRRT treatment and long mechanical ventilation time during ICU are more likely to have bone loss.