DISCUSSION
In this study the prevalance of sarcopenia was found to be 59% in the
patients admitted to general ICU in a one-year period and most common in
patients over 70 years of age. Sarcopenia was associated with the
increasing in mortality, the prolongation in the lenght of staying at
hospital and ICU.
EWGSOP reported the incidence of sarcopenia as 5.8-14.9% in the normal
population, 4.1% in men and 16.6% in women (2). On the other hand,
they reported that the incidence in the elderly was between 1-29% (17).
Moisey et al found this figure to be 71% in aged trauma patients (18).
However, the number of studies investigating the incidence of sarcopenia
in critically ill patients is low. Sheean et al found the incidence of
sarcopenia as 62% in patients who were admitted to ICU due to
respiratory failure and followed up in mechanical ventilator (19). Joyce
et al reported the incidence of sarcopenia in their patients
hospitalized in their intensive care unit as 68% (13). Baggerman et al
were reported that the prevalence of sarcopenia is approximately 30-70
% in intensive care units (5). In the present study, we found the
incidence of sarcopenia in general ICU as 59%, similar to literature.
Malnutrition is closely related to sarcopenia in aged persons and plays
an important role in the development of sarcopenia. Mundi et al showed
that 50% of the critically ill patients were malnourished, which is the
reason for impaired immune function, long-term ventilator dependence,
increased infectious complications, and increased morbidity and
mortality (20). It is important to evaluate the nutritional status of
first admission in patients admitted to ICU, but it is difficult to
assess the history of acute weight loss. Protein deficiency disrupts the
immune system by increasing metabolic stres (21). Baumgartner et al
found an association between albumin levels and sarcopenia (22). Kim et
al reported that higher albumin levels were associated with a protective
effect against declines in SMI (23). Although there was no difference in
albumin levels in our patients, we found prealbumin levels lower in
patients with sarcopenia. Prealbumin is a protein produced by the liver.
Serum prealbumin had historically been used as a biomarker of
malnutrition and as an important indicator of overall nutrition status
among aged adults not suffering from acute illness. Chen et al reported
that lower prealbumin levels were associated with higher sarcopenia
prevelance. Therefore higher BMI and prealbumin levels may be protective
factors against sarcopenia development among aged adults (24). We
consider that muscle mass or strength might decline due to degradation
of protein synthesis associated with low prealbumin, which may lead to
an increased risk of sarcopenia in critical illness.
BMI is a parameter used in the evaluation of nutrition, based on height
and weight. But body weight includes both fat and muscle mass.
Therefore, it prevents us from making the accurate assessment for
sarcopenia. Weijs et al reported that the measurement of muscle mass was
a more important indicator than BMI (25). In some studies, acute
sarcopenia due to muscle destruction and decreased protein synthesis has
been shown in critically ill patients. Muscle volume decrement was shown
as 17-30% in the first 10 days of the ICU (26). The use of BMI may also
cause inaccurate results in the presence of diffuse edema, especially in
obese patients. Albumin or other serum proteins are affected by the
acute phase response and changes in the intravascular volume so prevent
the use of as a marker for the assessment of nutritional status in the
critical patient (27). In CT imaging, body compartments can be better
distinguished, and abdominal fat tissue, visceral adipose tissue,
intramuscular, and subcutaneous adipose tissue can be identified more
accurately. Therefore, abdominal CT is defined as standard method for
evaluating total body and skeletal muscle (21). Sheetz et al evaluated
SMI in abdominal CT preoperatively and reported sarcopenia (28). Martin
et al reported that SMI was closely related to mortality and associated
with poor prognosis, especially in the aged patients (29). In the
present study, abdominal CT was used for SMI evaluation. Patients were
divided into two groups for SMI values based on Prado’s threshold values
(16). SMI was found to be lower in patients over the age of 70 compared
to those older than 40.
The general ICU population is very heterogeneous. The mortality of
critically ill patients is still one of the most important issues,
especially for the elderly patients with comorbidities. Most patients
have sepsis, and suffering from chronic comorbidities such as
cardiovascular failure, trauma, malnutrition or cancer. These
comorbidities are associated with a decline of skeletal muscle mass,
potentially leading to sarcopenia. Various scoring systems are used to
predict mortality. However, these scoring systems have shown relatively
poor predictable performance. We used APACHE II and SOFA scores in ICU.
However, we couldn’t find any differences between the groups.
In several studies, it has been stated that low levels of vitamin D
cause a decrease in muscle tension. Vitamin D deficiency should be
treated to maintain vitamin D levels of 40 ng/mL and above (29,30). Any
relationship between serum vitamin D levels and muscle mass was not
found in this study.
In the presence of sarcopenia; length of mechanical ventilation, length
of stay in ICU and hospital are longer and consequently an cost
increases (28). Moisey et al found the number of days on ventilator and
the number of days of intensive care to be higher. Hospital stay was
longer and mortality was higher in the sarcopenic patients (18). Weijs
et al they reported that low muscle mass evaluated with CT was related
to increased duration of mechanical ventilation and increased duration
of hospitalization and mortality (25). Kirk et al reported that the
presence of preoperative sarcopenia increases the incidence of admission
to the intensive care unit and prolongs the duration of discharge (21).
The patients were admitted to ICU with a severe critical disease
accompanied by comorbidities, protein catabolism, muscle atrophy and
weakness. Sarcopenia caused an increase in mortality, a prolongation in
the lenght of hospitalization and ICU stay. In the present study,
mortality was increased and lengths of intensive care and hospital stay
were prolonged in the presence of sarcopenia,
Limitations of the study; it was a retrospective and single centered
study. Data were obtained directly from the medical records of the
patients. Patients with abdominal CT for any reason were included.
Primary or secondary sarcopenia could not be differentiated because
abdominal CT at any time was evaluated during the treatment in the ICU.
There were cases that could not be evaluated because of missing data.
Response to treatment could not be evaluated (adequate nutrition,
specifically protein and micronutrients such as Vit D).