Being male and obese are not risk factors for Covid-19 death, new study suggests
Research has in the past linked being male and obese as high risk factors for Covid-19 complications and death, but a new study by the University of Cape Town has now found that the two factors are not necessarily associated with increased mortality in patients admitted into intensive care.
It was initially found that being male and obese were risk factors due the impairment that weight gain has to the immune function and difficulties with ventilation, for instance.
But researchers have instead found that being a smoker, being hypertensive, diabetic and having a cardiovascular disease were more likely to lead to death than an increasing body mass index (BMI).
In a study published in medical journal Anaesthesia, it was found that patients with Covid-19 in ICU were 40% more likely to die if they had a history of smoking, were 54% more likely with a history of high blood pressure, 41% more likely with a history of diabetes, 75% more likely with a history of respiratory disease, and around twice as likely with a history cardiovascular disease or cancer, and 2.4 times more likely to die with a history kidney disease.
Researchers analysed 58 studies and more than 44,000 patients.
Prof Bruce Biccard, the study's lead investigator and second chair in the department of anaesthesia and perioperative medicine at UCT, said other factors associated with an increased risk of death were the severity of organ failure which needed mechanical ventilation by 2.5 times compared to non-ventilated ICU patients.
Those with elevated white blood cell counts and other markers of inflammation were also likely to die from Covid-19.
Analysing the reasons for the associations, the study found age may effectively represent frailty in Covid-19 patients which affects a person’s physiological reserve to overcome a critical illness.
“The findings confirm the association between diabetes, cardiovascular and respiratory comorbidities with mortality in Covid-19 patients. However, the reported associations between male sex and increasing BMI worsening outcomes are not supported by this meta-analysis of patients admitted to ICU. This meta-analysis provides a large sample size with respect to these risk factors and is a robust estimate of risk associated with male sex and BMI in critically ill Covid-19 patients.”
The risk factors of hypertension, smoking and respiratory disease may be linked by their association with angiotensin-converting enzyme (ACE) receptors in the body, as seen by the increased expression of ACE-2 receptors among smokers and patients with chronic obstructive pulmonary disease.
“The association between hypertension and cardiovascular disease and increased mortality may be linked to the risk of cardiac injury associated with the systemic inflammatory response to Covid-19 infection,” added Biccard.
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