[Analysis of the incidence and risk factors of sarcopenia in elderly intensive care unit patients: a prospective cohort study].

Abstract

Objective: To investigate and analysis of the occurrence and influencing factors of sarcopenia in elderly critically ill patients in the intensive care unit (ICU).

Methods: A prospective cohort study was conducted. Elderly patients (aged ≥ 60 years) admitted to the ICU of Tianjin Medical University General Hospital from November 2023 to June 2024 were enrolled. Clinical records were collected, and conduct muscle mass and strength measurements, as well as upper arm circumference and calf circumference were measured. Appendicular skeletal muscle index (ASMI) of less than 7.0 kg/m² for males and less than 5.7 kg/m² for females was defined as reduced muscle mass, grip strength of less than 28 kg for males and less than 18 kg for females was defined as decreased muscle strength, patients meeting both low muscle mass and low muscle strength criteria were diagnosed with sarcopenia. According to the diagnostic criteria for sarcopenia, patients were divided into sarcopenia group and non-sarcopenia group. Multivariate Logistic regression analysis was applied to identify risk factors for sarcopenia in the elderly and to develop a predictive model for the occurrence of sarcopenia. The predictive value of various risk factors for sarcopenia in elderly critically ill patients was evaluated by receiver operator characteristic curve (ROC curve). The Kaplan-Meier curve for the length of ICU stay of two groups patients were drawn.

Results: Finally, 540 elderly critically ill patients were included, including 43 patients with sarcopenia, and the incidence of sarcopenia was 8.0%. Univariate analysis showed that there were significantly differences in body mass index (BMI), number of hospitalizations in the past year, the length of ICU stay, ventilation mode, duration of mechanical ventilation, pre-admission exercise habits, nutritional support methods, upper arm circumference, calf circumference, and albumin infusion between the sarcopenia group and the non-sarcopenia group. Multivariate Logistic regression analysis showed that BMI [odds ratio (OR) = 0.79, 95% confidence interval (95%CI) was 0.67-0.93, P = 0.004], calf circumference (OR = 0.64, 95%CI was 0.54-0.76, P < 0.001), and duration of mechanical ventilation (OR = 1.06, 95%CI was 1.01-1.12, P = 0.034) were associated with an increased risk of sarcopenia in elderly critically ill patients. The ROC curve results showed that the area under the curve (AUC) and 95%CI of BMI, calf circumference, and duration of mechanical ventilation for predicting sarcopenia in elderly critically ill patients were 0.828 (0.767-0.888), 0.889 (0.844-0.933), and 0.397 (0.299-0.496), respectively, with cut-off values of 22.95 kg/m², 28.25 cm, and 50.50 days, respectively. The Kaplan-Meier curve showed that the cumulative survival rate of patients with sarcopenia was significantly lower than that of the non-sarcopenia group (Log-Rank test: χ ² = 5.619, P = 0.018).

Conclusions: Lower BMI, smaller calf circumference, and longer duration of mechanical ventilation are associated with an increased risk of sarcopenia in critically ill elderly patients.