The Correlation between Skeletal Muscle Index of the L3 Vertebral Body and Malnutrition in Patients with Advanced Lung Cancer

Abstract Background: By analyzing the L3 skeletal muscle index in patients with advanced lung cancer, we determined whether this index could be an independent predictor of malnutrition in such patients and its role in nutritional assessments.Methods: Retrospective analysis was performed on patients with advanced lung cancer who received medical treatment at the Cancer Center of The First Hospital of Jilin University from January 2017 to July 2017, and relevant data were collated and analyzed. Abdominal CT was used to analyze the L3 skeletal muscle index, and PG-SGA score, body mass index (BMI), and serological indicators were analyzed. According to PG-SGA scores, patients were divided into severe malnutrition (≥9 points), mild to moderate malnutrition (≥3 points and ≤8 points), and no malnutrition (≤2 points) groups. Pearson correlation analysis was conducted between the skeletal muscle index and PG-SGA score, BMI, and laboratory test indices. Univariate and multivariate logistic regression analyses were conducted on the factors related to malnutrition, and a forest plot was drawn to identify malnutrition risk and protection factors.Results:1. The age of patients in the severe malnutrition group, the mild to moderate malnutrition group, and the no malnutrition group significantly differed, with mean ages of 63.46±10.01 years, 60.42±8.76 years, and 55.03±10.40 years, respectively. Furthermore, the NLR of the severe malnutrition group was significantly higher than that of the no malnutrition group, with statistical significance. The difference between the mild to moderate malnutrition group and the no malnutrition group were not statistically significant, with NLRs of 4.07±3.34, 3.09±1.47, and 2.47±0.92, respectively. The L3 skeletal muscle mass indices of patients in the severe malnutrition and mild to moderate malnutrition groups were significantly lower than that of the patients in the no malnutrition group, with statistical significance. The L3 skeletal muscle mass index of patients in the severe malnutrition group, mild to moderate malnutrition group, and no malnutrition group were 27.40±4.25 cm2/m2, 38.19±6.17 cm2/m2, and 47.96±5.02 cm2/m2, respectively.2.The multivariate analysis showed that the L3 skeletal muscle index was an independent risk factor for malnutrition (OR=0.627, p=0.000; OR=0.454, p=0.000).3.The Pearson correlation analysis showed that the PG-SGA score positively correlated with age (r=0.296), but negatively correlated with L3 skeletal muscle mass index (r=-0.857) (P≤0.05). The L3 skeletal muscle mass index also negatively correlated with age (r=-0.240) (P≤0.05).Conclusion：1. The differences in the L3 skeletal muscle index, age, PA, and NLR were statistically significant among patients with advanced lung cancer with different nutritional statuses.2. In the nutritional assessment of patients with lung cancer, the L3 skeletal muscle index was consistent with the PG-SGA.3. The L3 skeletal muscle index is an independent predictor of malnutrition in patients with advanced lung cancer.