Introduction
Coronavirus disease 2019 (COVID-19) is a new respiratory disease that
first appeared in Wuhan, China (1). The COVID-19 disease has killed more
than 5 million people globally (2) and has affected the lives of
millions of people around the world due to the quarantine of cities,
business closures, and social distancing (3). COVID-19 is associated
with many health problems. One of these important complications is
severe acute respiratory syndrome (4). Since the outbreak of this
contagious disease, the number of cases has increased rapidly and it has
affected all age groups and people all over the world (5). COVID-19
patients hospitalized in the ICU often need mechanical ventilation and
extracorporeal membrane oxygenation, which increases treatment costs
(6). The financial crisis caused by this virus causes mental problems
and suicide among people (7). The complications caused by this virus
include pulmonary, cardiovascular, neuropsychiatric, hematologic,
gastrointestinal, renal, endocrine, dermatologic, and musculoskeletal
problems (8). However, the mechanism of the effects of factors causing
long-term complications of COVID-19 is not yet clear.
There are several factors that affect COVID-19 incidence such as age,
lung disease, hypertension, heart disease, kidney disease, or metabolic
disorders. There are also other factors like physical distance,
ventilation, face masks, socioeconomic factor, vaccination, SARS-CoV-2
variants, and the availability of COVID-19 testing that are helpful in
this virus prediction (9). In critically ill patients with Covid-19, the
body’s metabolism may experience severe disturbances. For example, the
function of pancreatic beta cells is often affected and the regulation
of blood glucose is disturbed (10). Poor nutrition of critically ill
patients may be associated with increased length of stay in the
intensive care unit (ICU) and higher mortality (11). Due to the
persistent pro-inflammatory immune response, the risk of nutritional
stress such as malnutrition is higher in patients with COVID-19.
Previous studies reported that enteral feeding does not necessarily
improve the status of COVID-19 patients (12). The results of one
meta-analysis study indicated that early enteral nutrition is associated
with a lower risk of mortality and SOFA (Sequential Organ Failure
Assessment) score compared with delayed enteral nutrition in critically
ill COVID-19 patients but it did not significantly
(p >0.05) reduce the length of hospital stay, length
of ICU stay and days on mechanical ventilation compared to delayed
enteral nutrition or parenteral nutrition, respectively (13). Another
meta-analysis showed that mortality was reduced in the early enteral
nutrition group compared with the delayed enteral group. It has also
been indicated that enteral nutrition may be the preferred route to
enhance the integrity of the gut and promote immune function (14). The
present study aimed to investigate the association of enteral feeding
with biochemical and pathological indices associated with
survival/mortality in COVID-19 patients.