INTRODUCTION

The disease caused by the new coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2), enveloped RNA viruses, commonly found in humans, demonstrates a broad spectrum of severity and lethality in patients with no apparent symptoms. These and other factors contributed to its rapid spread globally and its conFiguration in a pandemic ¹.

The impact of the chaos that this pandemic has presented can be demonstrated by the number of people infected and the number of deaths already registered. Considering the official records so far (11/11/2020), 51,251,715 cases of COVID-19 and 1,270,930 deaths have been confirmed worldwide. And in the Region of the Americas, 14,387,350 people who were infected with the new coronavirus were recovered from the disease. Brazil had a total of 5,224,362 confirmed cases of coronavirus ².

The spectrum of the disease is broad and includes mild and self-limited conditions up to severe and progressive atypical pneumonia, multiple organ failure, and death. The people who have characteristics prone to develop more severe forms of the disease and with a higher risk of death are the elderly, diabetics, or those with cardiovascular, respiratory, or kidney diseases³.

Another population at increased risk of developing more severe forms of the disease is people with obesity. Such morbidity can be defined, in a simplified way, as a disease characterized by excessive accumulation of body fat due to the positive energy balance and which has repercussions on health, with a significant loss in quality and time of life ⁴.

People who have this disease can develop severe forms of COVID-19, which may present a decrease in lung function, changes in the microbiota, an increase in pro-inflammatory substances, and changes in the immune response⁵, constituting a severe risk for hospitalization⁶.

The unfavorable effects of obesity in viral infections have been attributed to metabolic breakdown and chronic inflammation of fatty tissue deposits, leading to blunted macrophage activation and impaired T and B lymphocyte responses⁷.

Given the above, this study is justified by the need to have a more in-depth approach concerning the clinical characteristics and outcomes in people with covid-19 and obesity, allowing particular attention for this public, both on the part of health professionals public health policies. Considering that patients with obesity have a decisive predictive factor for the worsening of the clinical conditions of covid-19, and also due to the scarcity in the national literature on the subject, the present study aimed to identify the outcomes and clinical characteristics of people with obesity and covid- 19 in national and international scientific literature.

METHOD

It is an Integrative Literature Review, a method that has the following steps: 1) elaboration of the review question; 2) search and selection of primary studies; 3) extraction of data from the studies; 4) critical evaluation of the primary studies included in the review; 5) synthesis of the results of the review and 6) presentation of the method⁸.

The research question was formulated according to the acronym PICo (P - Population; I - Phenomenon of Interest; Co - Context⁹ and the following structure was considered: P - people with obesity; I - clinical characteristics; Co - in COVID-19 times. Thus, the next question was asked: "What are the clinical characteristics presented by people with obesity with a confirmed diagnosis of COVID-19 and its impact on health?"

The strategy for identifying and selecting the studies was to search for publications indexed in the Medical Literature and Retrieval System on Line database (MEDLINE / PubMed®), and Virtual Health Library (VHL) in November 2020, with the descriptors in health sciences (DeCS): obesity, covid-19, and clinical characteristics, using among them the Boolean operator and. The following criteria were adopted to select articles: original articles in total, available online in the selected databases, and published in Portuguese, English, and Spanish, with a time frame from 2019 to 2020. Review articles, theses, dissertations, non-scientific materials, or papers that were not related to the theme and those duplicated in the databases.

Out of the material obtained, there were 121 articles in the VHL, after the exclusion of the repeated ones, 90 articles remained. In MEDLINE there were 112 articles, one being repeated. Each abstract/article was read, highlighting those that responded to the objective proposed by this study to organize and tabulate the data. For the organization and tabulation of data, the researchers developed a data collection instrument containing: names of authors, year of publication, country of study, category of research, study population, results, and conclusion. Following the inclusion criteria, studies were selected for a complete evaluation, with 13 chosen for characterization.

Figure 1:  Flowchart of study selection according to PRISMA. Picos, Piauí, Brazil, 2020 

RESULTS

Of the 13 articles analyzed in total, all were published in international journals, most of which were conducted in the United States (n = 5), followed by China (n = 4), all in 2020. Regarding the method adopted in the surveys, retrospective cohorts predominated.

The publications covered the outcomes and clinical characteristics of COVID-19 in patients with obesity, mostly the context of the health service that the surveys were developed, hospitals predominated, with samples ranging from 65 to 383 participants.

Chart 1:  Summarization of the descriptive characteristics of the articles included (n = 13). Picos, PI, Brazil, 2020. 

DISCUSSION

Regarding the origin of the surveys, it is noted that all were done in other countries. Most studies have been published in the USA referring to the clinical situation of the population since they live in an obesity epidemic. They were followed by China, where the coronavirus appeared, in 2019.

Regarding the objectives of the studies, four articles investigated the clinical characteristics of people with covid-19 and obesity, three the risk factors of people with covid-19 and obesity, and the others the severity of people with covid-19 and obesity. Regarding the type of study, eight articles were from a retrospective cohort.

Recent studies have shown a strong association of worse clinical outcomes in COVID-19 disease with obesity, even in the absence of any other comorbidity. A unicentric French study found that obesity was present in 47.6% and 28.2% of severe cases, respectively. Simultaneously, the need for interventional mechanical ventilation increased with the categories of BMI, regardless of age, diabetes, and hypertension¹⁰.

Obesity influences clinical outcomes during SARS, being proposed as a cause of mortality and adverse clinical outcomes for severe cases of influenza due to mechanical and immunological factors. In cases of COVID-19, obesity was consistently associated with adverse outcomes¹¹, with the comorbidity that conferred an increased risk of death exclusively for COVID-19 compared to non-COVID-19¹².

In addition to the harmful effects on host immunity, in the context of the disease by the new coronavirus, obesity has been shown to affect lung function in several ways, related to the mechanical and inflammatory aspect, increased expression of ACE2 (angiotensin-converting enzyme 2), increased diversity and viral titers and prolonged virus elimination¹³, reduction in expiratory volume and forced vital capacity⁵. Thus, it makes the person with obesity more susceptible to presenting respiratory symptoms and promoting progression to respiratory failure¹⁴.

Such morbidity systematically induces chronic inflammation by increasing the secretion of cytokines, such as interleukin 6 (IL6), interleukin 8 (IL8), and tumor necrosis factorα, which can aggravate the damage to the lung parenchyma and bronchi¹⁵. This inflammation in obesity can worsen the acute inflammatory response triggered by a SARS-CoV-2 infection, associated with a cytokine release syndrome¹⁶.

Regarding the evidenced clinical outcomes, a study showed a high mortality rate in patients admitted with covid-19 who were obese compared to those without obesity and longer hospital stay¹⁷. Another study revealed a higher admission rate to the ICU in obese people than those without obesity¹⁸. Another finding was longer oxygen therapy time, increased severity of covid-19 in people with obesity¹².

A study carried out with young people showed that obesity is a risk factor for morbidity rates in younger people, predispose to risk of more serious diseases and influence the progression and prognosis of COVID-19¹⁹.

Regarding the clinical characteristics mentioned in this research, they demonstrated that ferritin tended to remain higher in the group of obese people. These patients were more likely to have fever, cough, and shortness of breath, low serum albumin level, high levels of direct bilirubin, lipoprotein, and C-reactive protein (CRP). The neutrophil count was also higher and showed more severe pathological changes in the lung and upper blood lymphocytes, triglycerides, IL-6, CRP, cystatin C, alanine aminotransferase, erythrocyte sedimentation rate²⁰.

The characteristics mentioned above are due to low-grade chronic inflammation that characterizes obesity and results in metabolic and immunological disorders. As the pathophysiology of SARS-CoV-2 infection is being clarified, the links between the severity of the clinical presentation and the dysmetabolic background are revealed. Dysfunctional hypertrophic adipocytes in obesity produce an excessive amount of cytokines, such as IL-6, IL-8, monocyte-attracting protein-1, leptin, and plasminogen activator inhibitor-1 (PAI -1), among others, which leads to increased recruitment of macrophages, especially polarized M1 macrophages²⁰.

These cells, in turn, produce large amounts of pro-inflammatory molecules such as IL-1, IL-6, IL-8, TNF, and MCP-1. This effect is also enhanced by the action of increasing circulating levels of fatty acids free. The cumulative effect of these actions is a state of chronic inflammation and hypercytokinaemia, which leads to defective innate immunity and creates a favorable basis for the hyperinflammatory response mediated by macrophage activation syndrome in severe COVID-19 cases²¹.

Given the articles selected for review, it becomes evident that obesity together with covid-19 hinders is a potential risk factor for worsening prognosis, the evolution of the patient's cure, and even death. Thus, it needs treatment with specialized care for such an audience.

CONCLUSION

It was found that obesity in people with covid-19 is an important predictor of severity, enhancing clinical characteristics such as cough, fatigue, fever, and tiredness. Also, clinical outcomes include the potential risk of complications, high mortality rates, greater need for admission to the ICU, greater propensity to be intubated, and longer oxygen therapy time. Thus, more attention should be paid to these patients by health teams, from admission to discharge.

As a recommendation, it is essential to make the general population aware of the severity of covid-19 in people with obesity so that preventive measures are enhanced, and contamination among this public is reduced to the maximum possible. Given the importance of the subject, it is necessary to carry out more studies, mainly national, since none was identified in the research, to investigate the clinical characteristics and outcomes of people with obesity and covid-19 for a better knowledge of which intervention is safer and more effective in the face of this situation.