Sarcopenia: it is time to attach more importance to this stealth killer in patients who are critically ill

We read with great interest the recent article by Gustafson et al. [1]. The study evaluated the musculoskeletal health status of intensive care unit (ICU) survivors. Their findings suggested that, among 254 patients admitted to the ICU, 59% had musculoskeletal problems yet only 24% received physical therapy after discharge. Given the high incidence and risk of musculoskeletal disorders in patients who are critically ill, the importance of this study deserves to be recognised. However, when it comes to musculoskeletal diseases, sarcopenia is an important topic. This study focused on specific musculoskeletal outcomes rather than the occurrence and development of sarcopenia in this group of patients and its impact on patient prognosis. At present, the research on sarcopenia has mainly focused on older patients. However, it is worth noting that the incidence of sarcopenia is high in patients who are critically ill. Meyer et al. looked at 1563 critically ill patients with different underlying diagnoses [2]. The pooled overall prevalence of computed tomography (CT)-defined low skeletal muscle mass was 50.9%. Another meta-analysis comprising 3582 patients in ICU receiving mechanical ventilation showed an incidence of sarcopenia ranging from 22% to 71%, with a pooled prevalence of 43% [3]. Sarcopenia was also significantly related to increased mortality and longer durations of mechanical ventilation, ICU and hospital stay [3]. Hanna suggested that if patients who are critically ill subsequently develop sarcopenia, it will be a "deadly intersection" with a poor prognosis [4]. While Gustafson et al. [1] and previous studies [5] have shown that musculoskeletal diseases are associated with multiple adverse outcomes in patients who are critically ill, current clinical guidelines still lack clear direction on standards, systemic treatment and management options for sarcopenia. Although technologies such as dual-energy x-ray absorptiometry (DEXA), CT and magnetic resonance imaging have proven useful in measuring muscle mass, methods for measuring muscle mass in special populations, such as those with critical illness, have not yet been incorporated. Due to the complex condition of these patients, standardised methods and techniques for muscle mass measurement should take these special circumstances into consideration and require wider validation and application. Therefore, significant knowledge gaps exist regarding the diagnosis and treatment of sarcopenia in patients who are critically ill, and further research and guidance are urgently needed to improve clinical practice. We would like to see further information from this study on the occurrence of sarcopenia in this ICU population and its impact on patient outcomes. We also urge clinicians to pay more attention to musculoskeletal problems in patients with critical illness, especially sarcopenia.