INTRODUCTION
Sarcopenia was first described by Irwin Rosenberg in 1989, who defined sarcopenia as a condition of age-related loss of muscle mass [1]. In 2009 The European Sarcopenia Study Group (EWGSOP) defined sarcopenia as “a syndrome characterised by progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and death” [2]. In the fourth decade of life, muscle mass and appendicular skeletal muscle strength begin to decrease. A reduction of 3% or more in the functional capacity of the muscle from the age of sixth decade and a loss of more than 50% muscle mass from the eighth decade [3]. The prevalence of sarcopenia has been reported by EWGSOP as 5-13% and 11-50% for 60-70 years and over 80 years of age respectively [4]. In a study using computed tomography (CT) in intensive care unit (ICU), the frequency of sarcopenia was found to be 15-50 % in cancer patients, 30-45 % in patients with liver failure and 60-70 % in critically ill patients [4,5]. It is expected that it will affect 1.2 million people in 2025 and 2 million people in 2050 [6].
The distinctions of ‘primary sarcopenia’ and ‘secondary sarcopenia’ have been proposed by EWGSOP. Primary sarcopenia indicates muscle wasting related to aging, while secondary sarcopenia, refers to muscle loss related to inflammation or malnutrition. Because it is mostly due to multiple reasons, classification as primary or secondary may not always be reasonable [3]. Considering that the muscle mass is approximately 60% of the body weight, the pathological changes due to the excessive losses may have very large clinical consequences, especially in an aged population [2]. Clinical examination is used for the diagnosis of sarcopenia, where hand-grip strength is less than 20 kg in women and less than 30 kg in men and gait speed is below 0.8 m/sec. Sarcopenia in trunk muscles is a dominant risk factor that adversely affects prognosis. However, it is not possible for every patient to be diagnosed with clinical examination in ICU patients. Since radiological examinations show the relationship between total body fat and muscle mass, they can be used in the diagnosis of sarcopenia. Abdominal computerized tomography (CT) is accepted as the gold standard methods for diagnosing sarcopenia by fully evaluating fat tissue and muscle mass [2]. In the abdominal CT, L3 vertebra region is correlated with the muscle mass in the whole body. Therefore, the cross-sectional total area (with adipose tissue and skeletal muscle) is evaluated in abdominal CT including psoas, paraspinal muscles (erector spinae, quadratus lumborum) and abdominal wall muscles (transversus abdominis, external and internal obliques, rectus abdominus) at the level of L3 vertebra. In order to normalize the skeletal muscle index (SMI) according to the height, the total muscle area is divided by the square of the height and is defined in unit of cm2/m2 [6,7]. Similarly, the evaluation of the thickness of the psoas muscle in the lumbar 3rd or 4th vertebra may help in determining mortality after major surgery [8,9]. The measurement of the anterior-posterior diameter of the transverse psoas muscle at the umbilical level and the normalization by dividing the height is another radiological parameter used in the diagnosis [10].
Sarcopenia may not be considered in patients when first admission to ICU. They are all known to be negatively associated with ICU survival. It is important to predict mortality and stratify the risk of death in ICUs. There are few studies evaluating the frequency of sarcopenia and its relation with mortality in the ICU. Although there are articles about the relationship between sarcopenia and mortality [11,12]. There are also articles reporting that there is no relationship [13]. In this study, it was aimed to evaluate the diagnosis of sarcopenia by abdominal CT, the prevalence of sarcopenia and its relationship with prognosis in patients who are admitted to tertiary general ICU for a certain period, also to raise awareness of the intensivist about sarcopenia.