Assessment of muscle and fat mass in type 2 diabetes mellitus patients by dual-energy X-ray absorptiometry

Background: Obesity is an important health problem, as its prevalence has reached an epidemic level and continues to increase steadily resulting in higher risk of cardiovascular diseases and metabolic disorders. Currently, new methods and criteria are being developed to assess fat and muscle mass, as well as criteria for diagnosing obesity and sarcopenia.

Aim: To assess the quantitative composition of muscle and adipose tissue in type 2 diabetes mellitus patients based on the dual-energy X-ray absorptiometry for the diagnosis of obesity and sarcopenia.

Materials and methods: We examined 42 type 2 diabetic in-patients admitted to the Department of Therapeutic Endocrinology. Dual-energy X-ray absorptiometry was performed in all patients with subsequent assessment of the composition of muscle and fat tissue.

Results: If assessed by the body mass index, all patients had an excess body weight: median, 32.25 [29.75; 35.70]; in men, 31.3 [28.19; 34.63], in women, 32.29 [30.26; 36.54]. 26.2% of the patients (11/42) were overweight, but not obese. Female patients had more severe obesity than male (in total, 33.3% (10/30) of women had 2^nd and 3^rd degree of obesity, while men 16.7% (2/12)). The assessment by the fat mass index (FMI) showed that 2.4% (1/42) of the patients were normal-weight. Median FMI was 11.91 [10.40; 13.78] (in men, 8.86 [7.46; 12.1], in women, 12.35 [11.55; 15.47]). Overweight was found in 52.4% (22/42) of the patients; in total, 2^nd and 3^rd degree of obesity was observed in 25% (3/12) of the men and only in 6.6% (2/30) of the women. Median Appendicular Lean Mass Index (ALMI) in the total group was 7.99 [7.32; 9.05], being expectedly higher than in women: 9.19 [8.42; 9.45] and 7.58 [7.24; 8.49], respectively. Median T-score ALMI was 2.32 [1.73; 3.08], Z-score ALMI 2.15 [1.47; 3.54]. In general, there was a decrease in the appendicular muscle mass with age. There was an inverse correlation between the age and T-score ALMI (r = -0.319, р = 0.020), as well as between the age and Z-score ALMI (r = -0.634, p = 0.000). According to the results of T-score ALMI and Z-score ALMI, there were no patients with sarcopenia. However, the calculation of the T- and Z-criteria, corrected for fat mass, has led to a significant decrease of the medians of these parameters and allowed to identify a group of patients meeting the criteria of sarcopenia (97.6%, 41/42).

Conclusion: Based on ALMI, T-ALMI, and Z-ALMI, there were no patients with sarcopenia. After these criteria were corrected for fat mass, the number of such patients increased to 97.6% (41/42) and 85.7% (36/42), respectively. The potential use of the adjusted T-ALMI (FMI) and Z-ALMI (FMI) as criteria for sarcopenia and muscle mass reduction compared to the age-related normal values, as well as the classification of obesity by FMI should be studied in large epidemiological studies in different populations.