According to the current definition, sarcopenia refers to the progressive loss of skeletal muscle mass, strength and performance that increases risk of physical disability and hospitalization (1). Sarcopenia is believed to be a condition typical of advanced age, even if muscle mass loss begins around the age of 40 (1, 2). Nevertheless, while muscle mass represents the 42% of global body mass in adults, it drops to about 27% in the elderly (3). Sarcopenia’s negative effects can affect older subjects with a prevalence varying from 10% to 27% (4), increasing the risk of adverse consequences such as falls, fractures, depression, physical impairment, quality of life worsening, and increased mortality (5–8).

Sarcopenia pathophysiology is complex, with aging, sociodemographic factors, lifestyle choices, and a number of medical conditions being all factors that contribute (2). In particular, musculoskeletal aging and sarcopenia in the elderly have been demonstrated to be closely linked, since numerous studies have shown that cellular, mitochondrial and nervous impairment underlying ageing dysfunctions can also lead to the appearance of sarcopenia (9, 10). On the other hand, the adipose tissue redistribution represents another important age-related effect. In fact, as people age, subcutaneous adipose tissue declines gradually, visceral obesity increases, and adipocytes and lipids accumulate in the bone marrow, liver, and skeletal muscle (myosteatosis). In particular, total body fat increases with age until it reaches a plateau, and then it gradually begins to decline. Obesity and excessive caloric consumption can both contribute to the development of sarcopenia (11–13). Sarcopenia obesity supervenes when a decrease of lean body mass accompanied by an excessive accumulation of adipose tissue, particularly visceral fat, occurs (3, 14).

Even if musculoskeletal concerns are among the most common causes for older people to be admitted to a rehabilitation unit, to date, there are no studies that have investigated in real life the incidence of sarcopenia among elderly patients with musculoskeletal disorders. Therefore, our study aims to investigate the prevalence of sarcopenia (diagnosed through the algorithm proposed by the European Working Group on Sarcopenia in Older People-2 or EWGSOP-2) in a real-life cohort of patients over the age of 65 with musculoskeletal conditions referred to a Rehabilitation Unit on an outpatient basis. Given the association between sarcopenia and obesity, secondary aim of our study is to search for real-life associations between sarcopenia and changes in nutritional status and Body Mass Index (BMI) among a population of elderly subjects suffering from musculoskeletal concerns. Finally, quality of life and global health has been investigated in our population.

A total of 247 patients were enrolled in our study, with a median age of 73 years (range 61 – 95 years). Among them, 98 men and 149 women were studied ( Table 1 ). A percentage of 46.1% of subjects with overt sarcopenia was found and 10.1% showed a severe sarcopenia. The majority of the subjects presented a sarcopenia level 2 and low levels of global health, as assessed by the CIRS-SI ( Table 2 ).

Considering the different sarcopenia levels, the most severe level group (level 3) showed significantly lower values of BMI and MNA in comparison with all the other groups. Additionally, level 2 showed significant lower values in MNA, exclusively in comparison with level 0. Considering SF-12, only the physical composite score revealed slight significant differences. In particular, group 3 and group 1 presented lower values than group 0 ( Figure 1 ).

Concerning the arm and calf circumference, group 3 showed significant lower values for both the body parts in comparison with groups 0 and 1. Sarcopenia level 2 showed lower values than group 0 in CC ( Figure 2 ). Significant direct correlations were found between BMI and MUAC and BMI and CC (p< 0.01, r = 0.70 and r = 0.52 respectively). A minimal direct correlation was found between MNA and CC ( Figure 3 ).

In our study, elderly patients with musculoskeletal disorders who accessed the outpatient clinics of the University of Padua Rehabilitation Unit were shown to frequently present sarcopenia and low levels of global health, as assessed by the CIRS-SI score. In particular, the sarcopenia prevalence in our study reconfirmed data already present in the literature (24). In our work, we decided to apply ASMM because it is reliable and shows a relative cost-effectiveness. The application of the parameters calculated by the bioelectrical impedance and the use of SMM and ASMM allowed us a clear identification of the four groups, with different level of sarcopenia. The groups showed some peculiar differences and let us speculate about patients’ conditions and the different approaches to management.

Interestingly, when measuring BMI in patients referred to our center, we found that patients with severe sarcopenia had a sharp decline in BMI, whereas patients with probable sarcopenia and moderate sarcopenia had higher BMI scores that reached overweight levels. This agrees with the increasing evidence of an association between sarcopenia and obesity, while at extreme levels of sarcopenia not only muscle mass but also fat mass seem to be reduced.

Furthermore, our study showed that elderly subjects with musculoskeletal disorders are also prone to malnutrition and sarcopenia and malnutrition in this population seemed to be related. In literature, it has been demonstrated that specific foods and dietary habits can help prevent the loss of strength and function that comes with age (25, 26). Several randomized controlled trials seem to indicate that dietary protein consumption is essential for avoiding sarcopenia and muscle loss (26). Both selenium and magnesium have been investigated as dietary supplements, and they seem to have a possible relationship with physical activity and muscular function in older people (26). Improving diet and nutrition may be useful for both the prevention and treatment of sarcopenia as low nutritional status is widespread in the elderly, especially in frail subjects (12). Therefore, a proper rehabilitation program for elderly subjects with both sarcopenia and musculoskeletal concerns should include not only motor and strengthening exercises, but also educational initiatives to promote an adequate nutritional status. Progressive elastic band resistance exercises have been demonstrated to reduce fat mass and to increase physical function in patients with sarcopenic obesity and sarcopenia (27–30). Both water- and land-based activities have been shown to be beneficial in maintaining strength and in improving lower-body flexibility, with aquatic exercise appearing a better activity to improve dynamic balance and to manage comorbidities (31–35). Nutritional interventions should also be involved in the rehabilitative protocols suggested to these patients. Therefore, the rehabilitation team should include a nutrition expert, in order to help the patients receive the appropriate amount of protein as principal anabolic stimuli for muscle protein synthesis (1.0–1.2 g/kg body weight per day) and all the supplements that support the musculoskeletal health, such as vitamin D, antioxidant nutrients and long-chain polyunsaturated fatty acids (25, 36).

In our study, arm and calf circumference were shown to be reduced especially in patients with severe sarcopenia. Therefore, this study supports the use of these measurements for aiding in sarcopenia detection, reconfirming Hu et al. and Kawakami et al. findings (22, 23). They could therefore represent rapid indicators for the assessment of patients at increased risk of developing sarcopenia and thus be employed in clinical practice. A significant direct correlation between BMI and MUAC and CC circumferences was also obtained in our study, in accordance with previous results (37). Additionally, a slender direct association between MNA and CC was found. As a result, CC could be employed as a rapid outpatient tool for the assessment of the elderly patient nutritional status.

Our results showed also a moderate but significant reduction in the physical status category of quality of life in subjects with probable sarcopenia and severe sarcopenia when compared with the group of patients who did not present sarcopenia. This agrees with previous literature in which an association between quality of life and nutritional condition was found (38, 39). It is well-known that sarcopenia increases the risk of physical limitation and disability, lowering patients’ quality of life.

According to our data, patients with both sarcopenia and worse nutritional status reported reduced quality of life. By reducing malnutrition and encouraging optimal functioning, good nutrition can enhance the health-related quality of life (38). Since low physical capacity and quality of life influence personal and social costs (40), it can be hypothesized that the development of programs aimed at preventing nutritional deficiencies in patients with musculoskeletal disorders could contribute not only to ameliorate quality of life but also to economic and social benefits.

From the findings of our study, we can conclude that evaluations of sarcopenia, quality of life, and nutritional status should become part of the rehabilitative outclinics protocol for elderly patients accessing the Rehabilitation Unit for musculoskeletal concerns. The management of elderly patients with sarcopenia or pre-sarcopenia conditions associated to musculoskeletal disorders should start with the early detection of different concerns. An early assessment resulting in the identification of otherwise neglected needs may contribute to the development of primary and secondary prevention strategies, avoiding the progression into real pathological conditions (i.e., probable sarcopenia into sarcopenia, nutritional deficiencies into malnutrition) (41). Subsequently, a multimodal and multidisciplinary rehabilitation program, including prevention strategies, motor activity, strengthening exercise, nutrition and educative interventions (42, 43), should be proposed.

The study has several limitations that should be taken into consideration when interpreting the results. Firstly, there is a potential for selection bias as the participant selection process may not accurately represent the broader population of elderly individuals with musculoskeletal disease. Secondly, the generalizability of the findings may be limited due to the nature of observational studies. The specific inclusion and exclusion criteria, as well as the characteristics of the participants, may restrict the ability to extend the results to broader populations or different settings. Thirdly, despite attempts to control for confounding through statistical analysis or study design, there may be unmeasured or unknown factors that influence the relationship between the variables under investigation.

Real-life elderly subjects with musculoskeletal concerns are highly susceptible to sarcopenia. Therefore, rehabilitation for elderly patients with musculoskeletal concerns requires to be customized and multidisciplinary, addressing both the musculoskeletal condition and the needs associated to sarcopenia, including nutritional supplementation. To identify those who are more likely to develop sarcopenia, it is advisable to draw a user-friendly screening tool, e.g., using MUAC and CC. Nutritional assessment should be part of the screening process since early detection of a malnourished state may result in interventions to improve nutritional status and, as a result, quality of life. Future research should further investigate these aspects in order to enable the early identification of sarcopenia among elderly patients affected by musculoskeletal concerns and the formulation of customized multidisciplinary rehabilitative programs.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. The patients/participants provided their written informed consent to participate in this study.

Conceptualization and methodology, MM, DC, AF, YD and SM. Data collection, AB and MV. Data curation, MM, DC, AF, AB and NS. Data analysis, DC, AF and NS. Investigation, MM, DC, AB and MV. Writing—original draft preparation, MM and DC. Writing—review and editing, MM, DC, YD and SM. Supervision, SM. All authors contributed to the article and approved the submitted version.