'Bully' COVID-19 Picked on the Weakest, Show Excess Mortality Rates

Zarrin Hossain

January 11, 2022

Researchers looking at excess mortality during the first wave of the COVID-19 pandemic in 2020, noticed increased mortality in certain groups, including people with dementia, learning disabilities, or non-white ethnicity, according to a study from the London School of Hygiene and Tropical Medicine published in PLOS Medicine .

Excess mortality rates capture the total effect of the COVID-19 pandemic, as it is not affected by misspecification of cause of death, say the researchers.

"To our knowledge, there are no published analyses covering a wide range of health and demographic factors and comparing mortality rates pre-pandemic with those in the pandemic period within the same study population," said the study authors.

The researchers aimed to determine this correlation and analysed the records of 9,635,613 adults aged over 40 and registered at general practices in the UK that are part of the Clinical Practice Research Datalink. 

Overall Increase in Death Rates During the Pandemic

Using seasonally-adjusted time models, researchers compared all-cause and excess mortality in people with pre-existing health conditions and similar socio-demographic factors before and during the first wave of the COVID-19 pandemic, between March 5 and May 27, 2020. The relative risks (RRs) of all-cause mortality were also assessed.

After adjustment for seasonality, year, age, and sex, all-cause mortality increased by 43% (95% CI; 40% to 47%) across the whole study sample during the first wave of the pandemic compared with that expected based on pre-pandemic levels and trends (2015 to 2019). Most deaths occurred among the elderly population and in people who had pre-existing chronic conditions, notably hypertension, chronic kidney disease, and dementia.

However the number of excess deaths per million person-weeks varied greatly between these factors, for example with a 100-fold difference between those aged 40 to 49 and those aged 80 and over.

People with Dementia Most Affected

Overall, the relative risk (RR) of death remained relatively consistent pre-pandemic compared with during the first wave. However for a minority of factors, there were appreciable differences between the pre-pandemic and pandemic periods.

Most notably, before the pandemic, people suffering with dementia had an RR of death of 3.47 (95% CI 3.44 to 3.51) compared with those without dementia, but this increased to an RR of 5.07 (95% CI  4.87 to 5.28) during wave 1.

Similarly the RR for people with learning difficulties increased from 3.55 (95% CI 3.44 to 3.51) pre-pandemic to 4.82 (95% CI 4.35 to 5.34) during Wave 1.

Other health conditions identified with small increased RRs of death were cerebrovascular disease, being underweight, and having been diagnosed with cancer in the last year.

"The data show that everyone’s risk of dying, whatever the cause, increased by a similar amount during the first flush of the pandemic," said Dr Simon Clarke, associate professor in cellular microbiology, University of Reading.

"It’s good to have confirmation that the risks from COVID have been roughly proportional to the individual risks we all face in life – it serves to exaggerate any weaknesses we have," said Prof Sir David Spiegelhalter from the Winton Centre for Risk and Evidence Communication, University of Cambridge. "As the authors say, even if we all have a similar relative risk, the vulnerable start from a higher baseline and so have had a higher absolute risk of dying. For reasons that are not entirely clear, this virus picks on the weak and vulnerable. It is a bully" he said.

In addition, while before the pandemic mortality rates were lower in London compared with other regions of the UK (RR 0.89, 95% CI 0.88 to 0.89), during wave 1 mortality rates were higher in London than in other regions.

Compared with White ethnic groups, pre-pandemic mortality rates were lower in Black (0.80, 95% CI 0.78 to 0.82), South Asian (0.81, 95% CI 0.80 to 0.83), and other non-White ethnic groups (0.66, 95% CI 0.64 to 0.69). However, during wave 1 RRs of death in minority ethnic groups were higher compared with those of White people (Blacks 1.53, 95% CI 1.43 to 1.64; South Asians 1.15, 95% CI 1.08 to 1.23; other ethnicities 1.03, 95% 0.91 to 1.17).

Increase in Age Adds to Mortality Risk

The influence of age was also observed to change – every 5-year increase in age was associated with a 1.67 (95% CI 1.67 to 1.68) times greater rate of death in the pre-pandemic period compared with a 1.70 (95% CI 1.69 to 1.71) times greater rate of death during wave 1.

"The high mortality observed in some vulnerable groups, such as those with dementia and learning disabilities, should be a learning moment for the COVID-19 or other pandemic, and preventive measures should be implemented to avoid the spread of potentially fatal infectious agents," said the study authors.

"While for some people, this extra risk will have come from the risk of catching COVID-19 itself, others will have died in greater numbers due to other reasons influenced by the pandemic and its impact on their health," said Dr Clarke. "This study makes it clear that while all people across the UK faced a higher risk of dying than before, [the authors] do not attribute blame to any particular factor."

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