Introduction
Since severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) first appeared in Wuhan, China, 7,039,918 people around the world have been diagnosed with COVID-19 and 404,396 of them died [World Health Organization (WHO); accessed on 9th June 2020]. Again, according to WHO data, the first case in Turkey was confirmed on 11th March 2020, a total of 171,121 cases were diagnosed which corresponds to 2029 cases per 1 million population and 56 deaths per 1 million population.
Studies during the early period of the pandemic suggested that the disease had a more severe course in the elderly population, men, and those with comorbidities (1). Abdominal obesity is known to cause abnormal synthesis of adipokines and cytokines such as tumor necrosis alpha (TNF-alpha) and interferon, causing a chronic low-level inflammation that can damage the lung parenchyma and bronchi (2,3). Obesity appears to be a risk factor for COVID-19 cases.
The aim of this retrospective cohort study was to evaluate the relationship between the mortality caused by SARS-CoV-2 and the need to be followed in the intensive care unit (ICU) and body mass index (BMI).
Method
This retrospective cohort study was conducted in a single center. Starting from the first case on 11th March, 2020, all cases followed at the Infectious Diseases Clinic of Bezmialem Vakıf University Faculty of Medicine until 1st May 2020 were included. The diagnosis was made taking into account the updates of the Ministry of Health’s National COVID-19 Guide. The microbiological examination was performed by reverse transcription-polumerose chair reaction (RT-PCR) analysis of nasopharyngeal swab samples. From the database gender, age, BMI, RT-PCR result of nasopharyngeal swap samples, and follow-up and survival data in the ICU were analyzed. BMI values were grouped according to WHO criteria (<25 kg/m2= normal, 25-30 kg/m2= overweight, ≥30 kg/m2= obese) (4).
Statistical Analysis
Chi-square test and Fisher’s exact test were used to analyze the difference between the percentages of categorical data. The significance of the difference between the mean ages of the dead and survived patients was evaluated with the Student t-test and the significance of the difference between the medians of BMI was analyzed using the Mann-Whitney U test. Whether the BMI groups showed a trend in survival and follow-up in the ICU was analyzed with the chi-square trend and post-hoc z test.
Results
This study included 135 patients. Among them 57.8% (n=78) were males and the mean age was 52.5±16.1 years. The median BMI value was 27.7 (interquartile range: 24.1-31.2). The highest BMI was 56 kg/m2. In 39.3% (n=53) of the cases RT-PCR was positive in a nasopharyngeal swap and/or there were radiological findings + clinical features were compatible; in other cases, radiological and clinical findings were compatible. Fifteen cases were followed in ICU and 13 cases died (Table 1).
According to WHO classification 27.4% (n=37) were <25 kg/m2, 38.5% (n=52) were between 25-30 kg/m2 and 34.1% (n=46) were >30 kg/m2. Obesity (BMI >30 kg/m2) was more common among females (n=28, 49.1%) (p=0.002).
The median BMI value of cases followed in ICU (31.2 kg/m2) was higher than cases who were not followed in ICU (p=0.04). In addition, their mean age was (61.6±14.9) higher than cases followed at a ward (p=0.02). Comparison of the BMI groups according to follow-up in the ICU revealed that obese patients were followed in the ICU more than the other two groups (p=0.03).
The median BMI value of dead cases was (31.2 kg/m2) similar to the BMI value of survivors (p=0.09). The mean age of dead patients (62.9±14.5) was higher than survivors (p=0.01).
Subgroup analyses of dead cases revealed that the mean BMI value of females ≥60 years of age was similar to survivors (p=0.97). Among males in this age group, died cases were more frequently obese (BMI >30 kg/m2) than survivors (p=0.03) (Table 2). In both sexes, no mortality was observed in normal weight, overweight, and obese groups. In females, mortality was in cases above 50 years of age.
Discussion
COVID-19 continues to be an important health problem in Turkey as well as all over the World. Particular attention should be paid to elderly people with co-morbidities due to severity of illness, need for ICU, and the high risk of death in this group.
Obesity is known to be associated with many comorbid conditions. The aim of our study was to examine the effect of obesity in terms of survival and follow-up in ICU, considering age groups and gender.
There is an obesity epidemic all over the World. Obesity is also a growing health problem in Turkey. In the recent national health statistics data, it has been emphasized that the rate of obese people in both genders has increased (females 24.8% males 17.3%) (accessed from http://www.tuik.gov.tr/PreHaberBultenleri.do?id=33661). In 2017-2018 the prevalence of obesity in the USA was 42.4% and among them, 9.2% had BMI >40 kg/m2 (accessed from https://www.cdc.gov/obesity/data/adult.html). Obesity has negative consequences on the lives of individuals and communities. It is associated with many comorbidities (5). Obesity is accompanied by several COVID-19 risk factors (e.g diabetes mellitus, hypertension) (6). Obesity was observed to be associated with severe disease during the H1N1 epidemic (7). Experiences gained in the H1N1 epidemic can also provide insight into COVID-19 cases. Given the growing COVID-19 outbreak in countries with a high prevalence of obesity such as the USA, UK, and Mexico, clarification of the relationship between obesity and COVID-19 severity seems to be very important (8-11). A study conducted in France found that after standardization according to age and gender, the prevalence of obesity in severe COVID-19 patients was 1.35 times higher than the general French population (8). In contrast, obesity was not associated with mortality in the Chinese case series (1). However, although the rate of diseases associated with obesity such as diabetes, hypertension, and coronary artery disease was high in some case series reported from China, obesity was not reported among the underlying conditions (12,13). We couldn’t find a study from Turkey about the course of obesity in COVID-19 cases in our literature scan. The median BMI of the patients who died in our study was not different from the survivors.
In addition, according to the WHO classification, mortality rates in the obese group were not higher than in the surviving group. Simonnet et al. (14) demonstrated a relationship between obesity and disease severity in patients followed with a diagnosis of COVID-19 (14). In a study examining the recent national data in Mexico, higher mortality rates (13.5% vs 9.4%), hospitalization, and pneumonia were observed in obese COVID-19 cases. In addition, they noted that obese patients were followed in the ICU at a higher rate (5.0% versus 3.3%) and needed mechanical ventilation at a higher rate (5.2% versus 3.3%) (10). Similarly, another study demonstrated that the rates of being followed in the ICU in the presence of obesity were 1.89 times higher (8). In our study, the mean BMI of patients followed in the ICU was higher than those followed in the ward and the rate of obesity was higher in patients followed in ICU. A previous study demonstrated that mortality increased in the presence of obesity in patients <40 years old. In the same study obesity, early-onset diabetes mellitus, and accompanying co-morbidities also increased mortality (10). Unlike this, we did not observe the effect of obesity on mortality in young patients.
In a study examining New York City data, BMI >30 kg/m2 in COVID-19 cases <60 years of age was a risk factor for follow-up in the ICU (9). In the subgroup analysis of our study, mortality in >60 years of age males was higher than other age groups and females. This result suggested that factors affecting mortality in young patients should be evaluated.
Conclusion
In conclusion, the obesity epidemic in many countries, including the USA and Turkey, should cause worry as much as the COVID-19 pandemic. Obesity, by itself and with accompanying diseases, is a poor prognostic factor for many diseases including COVID-19. Therefore, it is clear that short and long-term national and international strategies should be determined in the fight against obesity.
Ethics
Ethics Committee Approval: Bezmialem Vakıf University Clinical Research Ethics Committee (no: 71306642-050.05.04-)
Peer-review: Externally peer reviewed.
Authorship Contributions
Surgical and Medical Practices: A.B.K., Concept: S.B., Design: S.B., Data Collection or Processing: M.E.Ö., Ç.E., Analysis or Interpretation: S.B., Literature Search: S.B., G.O., A.B.K., B.D., Y.A., M.M.K., Writing: S.B., M.E.Ö., Ç.E., G.O., B.S., A.B.K., B.D., Y.A., M.M.K.
Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: This work was supported by Gilead Sciences.