Type 2 diabetes is associated with an increased risk of sarcopenia, low muscle mass and low muscle strength (18). To estimate the probability of sarcopenia in functionally independent Chinese type 2 diabetes adults, we created a multivariate model based on the seven selected variables. Logistic regression analysis showed that male sex, low BMI, aging, high HbA1c, low protein intake and excessive daily caloric intake were risk factors that were independently associated with sarcopenia in type 2 diabetes. The AUC of the multivariable model was 0.818 (95% CI 0.756–0.880), which illustrated an excellent discrimination ability, and the Hosmer-Lemeshow test showed good fitness of the model. These results implied that type 2 diabetes patients in China would lose greater skeletal muscle mass and strength with aging, glucose level and total calorie and protein intake, which were in agreement with several previous studies (12, 19). The risk of sarcopenia in type 2 diabetes would decline with good control of glucose levels, a restriction of total calories, an increase in protein intake and the maintenance of a moderate BMI. The early identification of sarcopenia in type 2 diabetes would help clinicians to provide treatment as early as possible, which would be beneficial to improve the prognosis and quality of life of type 2 diabetes patients (20).
To facilitate clinical application, a new sarcopenia risk score for the detection of sarcopenia in type 2 diabetes patients comprising age, gender, BMI, glycosylated hemoglobin, insulin treatment or not, total calories per day and the proportion of calories supplied by protein was developed based on our data. The performance of the new sarcopenia risk score with high diagnostic accuracy was adequate for the detection and prediction of sarcopenia in Chinese type 2 diabetes patients aged 50 years and older. In our findings, the AUCs of the ROC curve representing the concordance statistics were 0.812 (95% CI 0.748–0.877) and 0.841 (95% CI 0.785–0.897) in internal and external validation, respectively, showing that the new sarcopenia risk score had good discrimination ability to identify high-risk sarcopenic patients among those with type 2 diabetes. The Hosmer-Lemeshow goodness-of-fit test in external validation showed that the new sarcopenia risk score had high accuracy to distinguish sarcopenia patients.
According to the current consensuses, diagnostic criteria from the EWGSOP (3) or AWGS (8) are still the gold standard for the diagnosis of sarcopenia; however, there are some shortcomings in the diagnosis process. The results of the diagnostic criteria were device-dependent and time-consuming and could differ based on the ethnic diversity of the cutoff points and the possible bias induced by body size and shape variations. Many medical institutions in China had no body composition instruments, and the X-ray exposure of dual-energy X-ray absorptiometry and high cost of computed tomography and magnetic resonance imaging restricted their widespread use in clinical practice. For this reason, the new, alternative sarcopenia risk score in our study was suitable for the detection of sarcopenia in type 2 diabetes patients when body composition could not be examined, had the advantage of being free of X-ray exposure and was a more practical and inexpensive choice than computed tomography, magnetic resonance imaging, or dual-energy X-ray absorptiometry. It was not difficult to acquire the parameters of the new, alternative sarcopenia risk score. BMI could be calculated by measuring height and weight, and glycosylated hemoglobin was a routine examination for type 2 diabetes patients that was carried out in many laboratories. Nutrient intake could be calculated by nourishment analysis software by reviewing the dietary diary. Furthermore, different from the SARC-F (5) and the Mini Sarcopenia Risk Assessment (MSRA) (6), which were developed and validated based on community-dwelling older adults, the new, alternative sarcopenia risk score in our study specialized in the population with diabetes, including nursing home residents or hospitalized older adults, who were at high risk of sarcopenia. Type 2 diabetes patients with sarcopenia were good candidates for intervention to prevent further physical disability given their potential for regaining muscle mass and the restoration of muscle function. In conclusion, the new, alternative sarcopenia risk score in our study was an effective and convenient health promotion tool instead of a diagnostic test and could become an alternative tool for endocrinologists to screen for sarcopenia in patients with type 2 diabetes.
The present study had several limitations that must be addressed. First, in the current study, the new, alternative sarcopenia risk score was validated in external populations that had similar clinical characteristics to the exploratory population, and further validation of the risk score in other parts of China is needed given the large diversity of the Chinese population. Second, the current analysis was carried out on a study population of Chinese type 2 diabetes adults. Therefore, our findings might not generalize to populations that do not have diabetes mellitus, those of other races/ethnicities or those in other countries.