Study identifies four main comorbidities associated with COVID deaths

The Griffith University meta-analysis, published in mBio, analysed global databases containing 375,859 participants from 14 countries and found chronic kidney disease was statistically the most prominent comorbidity leading to death.
 
Hypertension was the most common comorbidity in COVID-19 patients, followed by obesity and diabetes. But, despite having high prevalence, obesity was not associated with mortality in COVID-19 patients.
 
The new study is important as co-lead author Dr Adam Taylor said previous systematic reviews and meta-analysis have been limited by a lack of peer reviewed data and global clinical data.
 
‘Comorbidities are frequently cited as risk factors for severe COVID-19 outcomes; however, the degree to which specific comorbidities impact the disease is debatable,’ he said.
 
‘This is a global study covering all comorbidities reported to be involved in the exacerbation of COVID-19 leading to death. It allows us to identify specific comorbidities that have higher risk in patients and identify COVID-19 high-risk groups.
 
‘Further investigation is required to explain the higher prevalence of these comorbidities in COVID-19 patients, but studies may focus on the SARS-CoV-2 cell entry mechanism.’
 
According to the study’s lead author, viral immunologist Professor Suresh Mahlingam, the higher prevalence of these comorbidities in COVID-19 patients could be explained by the increased expression of the ACE-2 receptor used by SARS-CoV-2 for cell entry.
 
‘For example, diabetic patients can be prescribed drugs to control blood glucose that have also been shown to increase ACE-2 expression,’ he said.
 
COVID-19 has also been associated with increased clot strength, and Professor Mahlingam said severe outcomes in patients with hypertension and diabetes can be partially explained by the increased incidence of thrombotic complications, as these cohorts have an elevated risk.
 
‘These patients are commonly reported to have weakened immunological function which could predispose them to infections,’ he said.
 
‘In patients with chronic kidney disease, the risk of in-hospital mortality in COVID-19 patients also appears higher in cases with end-stage renal disease compared to chronic renal disease.’
 
PhD student Ng Wern Hann, who carried out the study, said patients with autoimmune diseases and cancer also suffered from weakened immunological function from the use of immunosuppressive drugs.
 
‘This may explain the increased risk of hospitalisation observed in these patients, particularly in those that are critically ill,’ he said.
 
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