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Do obesity and abnormal liver function magnify coronavirus symptoms?

Obesity and abnormal liver function have been predicted to play a part in extended hospitalization duration and worsen the health conditions of COVID-19 patients.

Image Credit: Featured image designed by this article's author, Rakshanda, using these two images.

Millions of people have been impacted by the COVID-19 pandemic. The recorded number of cases worldwide exceeded one million within four months. This has put the hospitalization surveillance system under high alert. Interestingly, hospitals have reported that in most of the patients admitted for this disease, some underlying factors are common among them.

Researchers at The Second Affiliated and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang conducted a study in February 2020 to determine if there are correlations between obesity, abnormal liver function, and length of hospital stay of COVID-19 patients. The experimental results showed that obesity and liver problems increase the severity of the infection as well as mortality. This study would help to identify preventive techniques and effective therapy.

A total of 58 patients – 36 men and 22 women – with mild symptoms of the viral infection participated in this study. The average age of the patients was 49 years. Patients were discharged if they had a normal body temperature for 3 days, lesser respiratory problems, and at least two negative test results. Their stay was considered long if it exceeded 19 days. The researchers calculated the body mass index of all the participants as a measurement of obesity, and checked each patient’s blood pressure. Under standard laboratory conditions, they collected blood samples for analysis. 

Alanine aminotransferase is an enzyme in the liver and kidney, and is usually found in low levels in the blood. Presence of higher levels of this enzyme points towards abnormal liver functioning. The levels of this enzyme were recorded for each participant to characterize abnormal liver function. Liver problems are known to be associated with inflammation in the body. So, the researchers analysed the blood samples for markers of inflammation such as white blood cell count, neutrophils, monocytes, serum creatinine level, C-reactive protein. Higher levels of these markers indicate some sort of inflammation in the body.

The researchers then performed statistical analyses to check how different the results are from the general population. These ultimately helped the group to estimate the factors which independently affected the time of discharge of the COVID-19 patients participating in this study.

In general, women had shorter hospital stays than men.  They categorized the participants as obese and not obese based on the BMI and alanine aminotransferase levels. Twenty-nine participants were found to be obese and 17 were diagnosed with liver problems. These 46 patients stayed in the hospital longer than the others. Compared to patients with a combination of both obesity and ALF, the patients with only one of the symptoms had lesser hospitalization duration. The patients with neither of the symptoms had the least duration of hospitalization. 

With this data, the researchers were able to infer that obesity and ALF could have a major influence on the hospitalization duration for COVID-19 patients. The higher the BMI, the longer the hospitalization time. Other American and European studies suggest the same about obesity – it is a potential risk factor for severe COVID-19 conditions. 

About one third of the world population is overweight and obese. Now with its influence in the longer duration of hospitalization and deterioration of health of COVID-19 patients, it has increased the health risks. The findings of this study propose that along with obesity even liver dysfunction can delay the recovery from this viral disease and also might be involved in its transmission due to this delay. 

An important protein in the transmission of the coronavirus is the angiotensin converting enzyme 2, or the ACE2. The virus attaches to ACE2 in order to enter the host cell. The expression of this protein is higher in fat cells compared to other body cells. This means that the presence of a large number of fat cells in the body increases the vulnerability to this viral infection. 

This study has its own technical shortcomings. It is a retrospective study, and the history and documentation of some patients was incomplete. Also, the study did not consider any medical treatment given to the  patients for liver dysfunction. The study was focussed on Chinese patients, so the results cannot be generalised to the world population. But it also cannot be ignored. Obesity and ALF are potential health risk factors. Their impact on the symptoms and health risks of COVID-19 patients is also notable. Hence, such patients should be clinically treated with extra attention and precaution.

Study Information

Original study: Clinical epidemiological analyses of overweight/obesity and abnormal liver function contributing to prolonged hospitalization in patients infected with COVID-19

Study was published on: June 22, 2020

Study author(s): Xiang Hu, Xiaoqiong Pan, Wei Zhou, Xuejiang Gu, Feixia Shen, Bo Yang & Zhen Hu

The study was done at: The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University

The study was funded by: National Natural Science Foundation of China, Wenzhou Science and Technology Bureau

Raw data availability: Not available.

Featured image credit: Featured image designed by this article's author, Rakshanda, using these two images.

This summary was edited by: Gina Misra