In the studies conducted in different countries during the first period of the global epidemia, it was found that most of the patients were male and advanced age (11, 12, 13). In one of the first studies on this field conducted in Wuhan, it was reported that the patients were mostly composed of elderly women and the most important diseases associated were hypertension, diabetes, heart diseases and COPD (14). Similar results to other studies (male ratio 67.2%, mean age 61.4 ± 15.9) were obtained in the study.
Hypertension was found to be the most common chronic disease associated with patients diagnosed with Covid-19 in the study (47.2%). High risk of serious disease in hypertensive patients was thought to be related; with the use of angiotensin converting enzyme 2 (ACE2) as the viral entry receptor in lung cells by the virüs, with the high prevalence of hypertension in the population, and the frequency of use of renin-angiotensin system (RAS) blockers (14). In the study, although fever in these patients is statistically significantly higher than other symptoms, the mechanism of this is not fully known. In different studies, it is emphasized that hypertension is a common comorbidity for COVID-19 infection, which significantly affects mortality and disease severity (11, 12, 15, 16).
The frequency of diabetes mellitus in the study was found to be 32.8%. With this rate, diabetes is the second most common disorder among the patients who participated in the study. For diabetes mellitus, Huang et al. has reported as the main comorbidity disease with a frequency of 20% (11). Its’ frequency was found around 10% in different studies (17).
Cardiovascular diseases are the third most common chronic disease group in the study (27.5%). Case series with additional cardiovascular disease have also been reported in the literature (18, 19).
Although the disease affects the respiratory tract; Huang et al (11) and Wang et al (18) found the prevalence of accompanying COPD to be 2% and 2.9%, respectively. Similarly, Chen et al. (19) found associated respiratory system diseases 1% in their study. In the study, COPD was seen at a very high rate with 8.3% and asthma 5.7%. These high rates found in the study have been associated with the high frequency of respiratory system diseases. In addition, although rare, bronchiectasis, interstitial lung disease and tobacco use have been reported as coexisting risk factors alone (12, 13, 20, 21). Moreover; in patients with asthma, the statistically significant excess of shortness of breath was associated with the clinical course of the disease.
Advanced DM, HT, neoplasia and heart disease patients with Covid-19 required significantly more intensive care. There was no relationship between the need for intensive care and the severity of the disease with COPD. This is an interesting finding that needs to be studied.
Neurological diseases are the disease group that cause the highest health burden especially in the elderly population (22). Despite this, no neurological disease was found in the records of patients diagnosed with Covid-19 in the study. Considering that neurological diseases require long-term follow-up and treatment; even if there is no Covid-19 diagnosis, special attention should be paid to the follow-up of these patients.
In the presented study, no findings regarding with digestive system disorders and Covid-19 were found. But; it has been reported that some patients with Covid-19 show digestive symptoms such as diarrhea, vomiting and abdominal pain, and the average liver enzyme levels of these patients are also high (23). Although it has been stated that inflammatory bowel diseases such as Crohn's and colitis ulcerosa may be additional diseases in Covid-19 in terms of genetic predisposition and environmental factors (24), no findings in this direction were found in the study. This is attributed to the certain study group in the intensive care unit.
In the presented study, cough (59.4%), fever (58.5%) and shortness of breath (45.9%) were found to be the most common symptoms. This situation was parallel to the literature (3, 19, 21).
In the conducted studies, leukopenia is the most common laboratory finding; rarely, thrombocytopenia is observed (3, 12, 25). In the literature, impairments have also been reported in liver and muscle enzymes. Abnormal elevations can also be observed in C-reactive protein, ferritin and d-dimer levels (16, 17). The study findings were also in line with data from the world.